Magnetoresistance effect element, magnetic memory array, magnetic memory device, and write method for magnetoresistance effect element

ABSTRACT

The present invention provides a magnetoresistance effect element with a high read operation speed, a magnetic memory array, a magnetic memory device, and a write method for a magnetoresistance effect element. A magnetoresistance effect element includes: a heavy metal layer; a magnetic recording unit including a recording layer that includes a ferromagnetic layer that is magnetized in a vertical direction with respect to a film surface and is provided on a front surface of the heavy metal layer, a barrier layer that is provided on a surface of the recording layer which is opposite to the heavy metal layer and is formed from an insulator, and a reference layer which is provided on a surface of the barrier layer which is opposite to the recording layer, and a magnetization of the reference layer is fixed in the vertical direction with respect to a film surface; an insulating layer that is provided on a surface of the heavy metal layer which is opposite to the magnetic recording unit; a first terminal that is connected to the insulating layer at a position facing the recording layer with the heavy metal layer and the insulating layer interposed therebetween and applies a voltage to the heavy metal layer through the insulating layer; a second terminal that is connected to the reference layer; and a third terminal and a fourth terminal which are connected to the heavy metal layer, and cause a write current to flow to the heavy metal layer between the magnetic recording unit and the insulating layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage entry under 35 U.S.C. § 371 ofInternational Application No. PCT/JP2019/015659, filed on Apr. 10, 2019,and which claims priority to Japanese Patent Application No.2018-090997, filed on May 9, 2018, both of which are hereby incorporatedherein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a magnetoresistance effect element, amagnetic memory array, a magnetic memory device, and a write method fora magnetoresistance effect element.

BACKGROUND ART

As a next-generation non-volatile memory that can obtain high speed andhigh rewrite resistance, a magnetic random access memory (MRAM) using amagnetoresistance effect element as a storage element is known. As anext-generation magnetoresistance effect element that is used for theMRAM, a spin-orbit torque magnetic random access memory (SOT-MRAM)element that reverses a magnetization of a magnetic tunnel junction(MTJ) by using spin-orbit torque has attracting attention.

The SOT-MRAM element has a configuration in which the MTJ including athree-layer structure of a ferromagnetic layer (also referred to as arecording layer)/an insulating layer (also referred to as a barrierlayer)/a ferromagnetic layer (also referred to as a reference layer) isprovided on a heavy metal layer. In the case of a Co—Fe-type magneticmaterial that is currently used, the SOT-MRAM element has properties inwhich resistance of an element is higher in an anti-parallel state inwhich magnetization directions of the recording layer and the referencelayer are anti-parallel in comparison to a parallel state in which themagnetization directions of the recording layer and the reference layerare parallel to each other, and data is recorded by associating theparallel state and the anti-parallel state with 0 and 1. In the SOT-MRAMelement, the magnetization direction of the reference layer is fixed,and magnetization reversal of the recording layer is possible, and thusthe parallel state and the anti-parallel state can be switched throughmagnetization reversal of the recording layer. In the SOT-MRAM element,a current is caused to flow to the heavy metal layer to induce a spincurrent by a spin-orbit interaction, and spins polarized by the spincurrent flow into the recording layer. According to this, amagnetization of the recording layer is reversed, and data is written.In addition, since the recording layer is magnetized in a direction ofeasy axis of magnetization, even when inflow of the spins disappears, amagnetized state is maintained, and thus the SOT-MRAM element storesdata.

In order to highly integrate the SOT-MRAM element, there is suggested anarchitecture in which a plurality of MTJs are arranged on the heavymetal layer (refer to Patent Literature 1). In the architecturedisclosed in Patent Literature 1, data is written to the MTJ by using amechanism in which magnetic anisotropy of the MTJ can be controlled byapplying a voltage to the MTJ. First, a voltage is applied to the MTJ towhich data is to be written to lower the magnetic anisotropy of therecording layer so as to cause the recording layer to enter a state(also referred to as a semi-selection state) in which magnetizationreversal is easy. Then, a write current is caused to flow to the heavymetal layer to reverse a magnetization of the recording layer, and thendata is written. In this manner, in a magnetic memory device of PatentLiterature 1, an MTJ to be written can be selected by applying a voltageto the MTJ.

CITATION LIST Patent Literature

Patent Literature 1: JP-A-2017-112351

SUMMARY OF INVENTION Technical Problem

However, in the architecture disclosed in Patent Literature 1, so as tocause the MTJ to enter the semi-section state, a voltage is also appliedto the MTJ even in writing. Therefore, a current also flows to the MTJeven in writing, and thus it is necessary to raise a withstand voltageof the MTJ by thickening the insulating layer so that the insulatinglayer constituting the barrier layer of the MTJ does not undergoinsulation breakdown even when applying a voltage to the MTJ for causingthe recording layer to enter the semi-selection state. However, when theinsulation layer is made thick, a resistance value of the MTJ becomeshigh, and read time delay occurs. As described above, in the SOT-MRAMelement of the related art, there is a problem that a write operation isfast but a read operation becomes slow when trying to integrate theelement.

Here, the invention has been made in consideration of theabove-described problem, and an object thereof is to provide amagnetoresistance effect element with a high read operation speed, amagnetic memory array, a magnetic memory device, and a write method fora magnetoresistance effect element.

Solution to Problem

According to an aspect of the invention, there is provided amagnetoresistance effect element including: a heavy metal layer; amagnetic recording unit including a recording layer that includes aferromagnetic layer that is magnetized in a vertical direction withrespect to a film surface and is provided on a front surface of theheavy metal layer, a barrier layer that is provided on a surface of therecording layer which is opposite to the heavy metal layer and is formedfrom an insulator, and a reference layer which is provided on a surfaceof the barrier layer which is opposite to the recording layer, and amagnetization of the reference layer is fixed in the vertical directionwith respect to a film surface; an insulating layer that is provided ona surface of the heavy metal layer which is opposite to the magneticrecording unit; a first terminal that is connected to the insulatinglayer at a position facing the recording layer with the heavy metallayer and the insulating layer interposed therebetween and applies avoltage to the heavy metal layer through the insulating layer; a secondterminal that is connected to the reference layer; and a third terminaland a fourth terminal which are connected to the heavy metal layer, andcause a write current to flow to the heavy metal layer between themagnetic recording unit and the insulating layer.

According to another aspect of the invention, there is provided amagnetic memory array including a plurality of the magnetoresistanceeffect elements according to any one of claims 1 to 8. The heavy metallayer of one of the magnetoresistance effect elements extends in a firstdirection, the extended heavy metal layer is shared by the otherplurality of magnetoresistance effect elements, and the magneticrecording units are arranged in the first direction on the front surfaceof the heavy metal layer.

According to still another aspect of the invention, there is provided amagnetic memory device including a plurality of the magnetic memoryarrays according to claim 9 or 10 which are arranged in a directionorthogonal to the first direction.

According to still another aspect of the invention, there is provided amagnetic memory device including: a magnetic memory array including aplurality of the magnetoresistance effect elements according to claim 7or 8, the heavy metal layer of one of the magnetoresistance effectelements extending in a first direction, the extended heavy metal layerbeing shared by the other plurality of magnetoresistance effectelements, the magnetic recording units being arranged in the firstdirection on the front surface of the heavy metal layer; a plurality offirst elongated terminals extending in a direction orthogonal to thefirst direction; and a plurality of second elongated terminals extendingin a direction orthogonal to the first direction. A plurality of themagnetic memory arrays are arranged in a direction orthogonal to thefirst direction, a plurality of the magnetic recording units arearranged in a direction orthogonal to the first direction, the firstelongated terminals are provided at positions facing the plurality ofarranged magnetic recording units with the heavy metal layer and theinsulating layer interposed therebetween, and the second elongatedterminals are provided at positions facing the plurality of arrangedmagnetic recording units, and are in contact with the diode.

According to still another aspect of the invention, there is provided awrite method for a magnetoresistance effect element including a heavymetal layer, a magnetic recording unit including a recording layer thatincludes a ferromagnetic layer that is magnetized in a verticaldirection with respect to a film surface and is provided on a frontsurface of the heavy metal layer, a barrier layer that is provided on asurface of the recording layer which is opposite to the heavy metallayer and is formed from an insulator, and a reference layer which isprovided on a surface of the barrier layer which is opposite to therecording layer, and a magnetization of the reference layer is fixed inthe vertical direction with respect to a film surface, and an insulatinglayer that is provided on a surface of the heavy metal layer which isopposite to the magnetic recording unit. The method includes amagnetization reversal process of applying a voltage to the heavy metallayer through the insulating layer, and causing a write current to flowbetween one end and the other end of the heavy metal layer to reverse amagnetization direction of the recording layer.

Advantageous Effects of Invention

According to the invention, since the insulating layer is provided onthe rear surface of the heavy metal layer, and the first terminal isconnected to the heavy metal layer at a position facing the recordinglayer with the heavy metal layer and the insulating layer interposedtherebetween, the magnetization of the recording layer can be reversedby applying a voltage to the heavy metal layer through the insulatinglayer, and causing a write current to flow to the heavy metal layer, anda current does not flow to the magnetic recording unit in writing.According to this, in the magnetoresistance effect element, it ispossible to reduce the resistance of the MTJ by reducing the thicknessof the barrier layer, and it is possible to speed up a read operation.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a perspective view illustrating a magnetoresistance effectelement of an embodiment of the invention, and FIG. 1B is across-sectional view obtained by cutting the magnetoresistance effectelement in FIG. 1A in an x-direction.

FIG. 2A is a schematic cross-sectional view describing a method ofwriting data “0” to a magnetoresistance effect element that is storingdata “1” and illustrates a state in which a voltage is applied to aheavy metal layer through an insulating layer, FIG. 2B is a schematiccross-sectional view describing a method for writing data “0” to themagnetoresistance effect element that is storing data “1” andillustrates a state in which data is written by causing a write currentto flow, FIG. 2C is a schematic cross-sectional view describing a methodfor writing data “1” to the magnetoresistance effect element that isstoring data “0” and illustrates a state in which a voltage is appliedto the heavy metal layer through the insulating layer, and FIG. 2D is aschematic cross-sectional view describing a method for writing data “1”to the magnetoresistance effect element that is storing data “0” andillustrates a state in which data is written by causing a write currentto flow.

FIG. 3 is a schematic cross-sectional view describing a method forreading data stored in the magnetoresistance effect element.

FIG. 4A is a schematic cross-sectional view describing another methodfor writing data “0” to the magnetoresistance effect element that isstoring data “1” and illustrates a state in which a voltage is appliedto the heavy metal layer through the insulating layer, FIG. 4B is aschematic cross-sectional view describing another method for writingdata “0” to the magnetoresistance effect element that is storing data“1” and illustrates a state in which data is written by causing a writecurrent to flow, FIG. 4C is a schematic cross-sectional view describinganother method for writing data “1” to the magnetoresistance effectelement that is storing data “0” and illustrates a state in which avoltage is applied to the heavy metal layer through the insulatinglayer, and FIG. 4D is a schematic cross-sectional view describinganother method for writing data “1” to the magnetoresistance effectelement that is storing data “0” and illustrates a state in which datais written by causing a write current to flow.

FIG. 5A is a schematic cross-sectional view illustrating amagnetoresistance effect element of a modification example of theinvention.

FIG. 5B is a schematic cross-sectional view illustrating amagnetoresistance effect element of another modification example of theinvention.

FIG. 5C is a schematic cross-sectional view illustrating amagnetoresistance effect element of still another modification exampleof the invention.

FIG. 5D is a schematic cross-sectional view illustrating amagnetoresistance effect element of still another modification exampleof the invention.

FIG. 5E is a schematic cross-sectional view illustrating amagnetoresistance effect element of still another modification exampleof the invention.

FIG. 5F is a schematic cross-sectional view illustrating amagnetoresistance effect element of still another modification exampleof the invention.

FIG. 5G is a schematic cross-sectional view illustrating amagnetoresistance effect element of still another modification exampleof the invention.

FIG. 5H is a schematic cross-sectional view illustrating amagnetoresistance effect element of still another modification exampleof the invention.

FIG. 5I is a schematic cross-sectional view illustrating amagnetoresistance effect element of still another modification exampleof the invention.

FIG. 6 is a schematic cross-sectional view illustrating a magneticmemory array of the embodiment of the invention.

FIG. 7A is a schematic cross-sectional view describing a method forwriting data to the magnetic memory array and illustrates a state inwhich a voltage is applied to the heavy metal layer through theinsulating layer, and FIG. 7B is a schematic cross-sectional viewillustrating a magnetoresistance effect element of still anothermodification example of the invention and illustrates a state in whichdata is written by causing a write current to flow.

FIG. 8 is a schematic cross-sectional view describing a method forreading data from the magnetic memory array.

FIG. 9A is a schematic cross-sectional view illustrating a magneticmemory array of a modification example of the invention.

FIG. 9B is a schematic cross-sectional view illustrating a magneticmemory array of another modification example of the invention.

FIG. 9C is a schematic cross-sectional view illustrating a magneticmemory array of another modification example of the invention.

FIG. 9D is a schematic cross-sectional view illustrating a magneticmemory array of still another modification example of the invention.

FIG. 9E is a schematic cross-sectional view illustrating a magneticmemory array of still another modification example of the invention.

FIG. 10A is a schematic cross-sectional view illustrating a magneticmemory array of still another modification example of the invention.

FIG. 10B is a schematic cross-sectional view illustrating a magneticmemory array of still another modification example of the invention.

FIG. 10C is a schematic cross-sectional view illustrating a magneticmemory array of still another modification example of the invention.

FIG. 11 is a perspective view illustrating a magnetic memory device ofthe embodiment of the invention.

FIG. 12 is a perspective view illustrating a magnetic memory device ofthe embodiment of the invention.

DESCRIPTION OF EMBODIMENTS (1) Magnetoresistance Effect Element ofEmbodiment of Invention (1-1) Overall Configuration of MagnetoresistanceEffect Element

Hereinafter, a magnetoresistance effect element 1 of an embodiment ofthe invention will be described with reference to FIG. 1A and FIG. 1B.FIG. 1A is a perspective view illustrating the magnetoresistance effectelement 1. In this specification, as illustrated in FIG. 1A, alongitudinal direction of a heavy metal layer 2 is set as an x-direction(an upper-right of a paper surface is +x-direction), a lateral directionis set as a y-direction (an upper-left direction of the paper surface inthe perspective is +y-direction), and a direction orthogonal to a frontsurface of the heavy metal layer 2 is set as a z-direction (an upperside of the paper surface is a +z-direction). In addition, FIG. 1B is aschematic view illustrating a cross-section of the magnetoresistanceeffect element 1 in the y-direction. In this specification, it isassumed that the +z-direction is referred to, for example, as an upperside, an upper portion, or the like, and the −z-direction is referredto, for example, as a lower side, a lower portion, or the like.

As illustrated in FIG. 1A, the magnetoresistance effect element 1includes the heavy metal layer 2, a magnetic recording unit 3 includinga magnetic tunnel junction (hereinafter, referred to as “MTJ”) includinga recording layer 10, a barrier layer 11, and a reference layer 12, andan insulating layer 5. In this embodiment, the heavy metal layer 2 has arectangular parallelepiped shape extending in a first direction(x-direction), and has a rectangular shape when viewed from an uppersurface. The heavy metal layer 2 has a rectangular parallelepiped shapehaving a length (length in the x-direction) of approximately to 260 nm,a width (length in the y-direction) of approximately 10 to 150 nm, and athickness (length in the z-direction) of approximately 0.5 to 20 nm. Inthe heavy metal layer 2, the width of the heavy metal layer 2 in they-direction is set to be greater than a width of the magnetic recordingunit 3.

The length of the heavy metal layer 2 is preferably as short as possibleas long as a current can pass therethrough, and in this case, a highdensity of a magnetic memory device including the magnetoresistanceeffect element 1 can be realized. It is preferable that the width of theheavy metal layer 2 is set to be the same length as the width of themagnetic recording unit 3, and in this case, the magnetoresistanceeffect element 1 has the highest write efficiency. It is preferable thatthe thickness of the heavy metal layer 2 is set to approximately 1 to 10nm. Note that, the length of the heavy metal layer 2 is a preferredlength when the heavy metal layer 2 includes one piece of the magneticrecording unit 3, and in a case where one piece of the heavy metal layer2 includes a plurality of the magnetic recording units 3 and themagnetic recording units 3 are arranged in the first direction, there isno limitation to the above-described length. The shape of the heavymetal layer 2 is preferably set as described above, but there is noparticular limitation.

As the heavy metal layer 2, a heavy metal in which a spin orbitinteraction is large, for example, Hf, Ta, W, Re, Os, Ir, Pt, Au, Pb,Pd, Rh, or an alloy that contains at least one or more among theseelements is preferable. As the alloy, for example, W—Hf, W—Ta, Pt—Au,Pt—Ir, Pd—Rh, and the like are particularly preferable. The heavy metallayer 2 has conductivity. Note that, when the heavy metal layer 2 isformed from Ir, Pt, Au, or an alloy mainly containing at least one ormore among these metals, a sign of a spin hall angle of the heavy metallayer 2 becomes positive, and when the heavy metal layer 2 is formedfrom Hf, Ta, W, Re, or an alloy mainly containing at least one or moreamong these metals, the sign of the spin hall angle of the heavy metallayer 2 becomes negative.

In this embodiment, the heavy metal layer 2 is formed from Pt—Au inwhich the sign of the spin hall angle is positive, and is formed in athickness of 7 nm. The heavy metal layer 2 is formed by forming a heavymetal film, for example, by a typical film formation method such asphysical vapor deposition (PVD) after forming a first terminal T1 to bedescribed later and the insulating layer 5 on a base layer (for example,an SiO₂ substrate or the like) or a circuit substrate (a substrate inwhich an FET-type transistor, a metal wiring, or the like is formed).The heavy metal layer 2 may be an amorphous layer or an epitaxial layerformed by epitaxial growth. The epitaxial layer represents a thin filmformed by epitaxial growth, and examples thereof include a singlecrystal layer, a layer that is generally a single crystal but partiallya polycrystal or the like, a layer that can be actually regarded as asingle crystal, and the like.

The magnetic recording unit 3 includes the recording layer 10 providedon the heavy metal layer 2, the barrier layer 11 provided on therecording layer 10 (a surface of the recording layer 10 which isopposite to the heavy metal layer 2), and the reference layer 12provided on the barrier layer 11 (a surface of the barrier layer 11which is opposite to the recording layer 10), and is provided on asurface of the heavy metal layer 2. The magnetic recording unit 3 isformed on the heavy metal layer 2 in a circular column shape, and has acircular shape when viewed form an upper surface. Accordingly, an aspectratio of the magnetic recording unit 3 is approximately 1. Here, theaspect ratio of the magnetic recording unit 3 stated in thisspecification represents an aspect ratio of a shape of the magneticrecording unit 3 when viewed from the upper surface. In a case where themagnetic recording unit 3 has a shape (or a cross-section in a widthdirection) such as a square shape and a circular shape in which themajor axis and the minor axis are not distinguished when viewed from theupper surface, the aspect ratio is 1. The aspect ratio is a ratiobetween a length of a long side and a length of a short side in the caseof a quadrilateral shape, and is a ratio between a length of the majoraxis and a length of the minor axis in the case of an elliptical shape.The aspect ratio is preferably approximately 1 to 1.5, and morepreferably approximately 1 to 1.3. In this case, it is possible tomanufacture a magnetic memory device in which magnetoresistance effectelements are arranged at a higher density in comparison to the relatedart. Note that, it is preferable that the aspect ratio of the magneticrecording unit 3 is set to approximately 1 to 1.5, and more preferablyapproximately 1 to 1.3, but the aspect ratio or the shape of themagnetic recording unit 3 is not particularly limited, and a cubic body,a rectangular parallelepiped body, an elliptical column, or the like isalso possible. For example, the magnetic recording unit 3 can have aquadrangular column shape with round corners.

In the magnetic recording unit 3, it is preferable that the length ofthe short side or the length of the minor axis (a length of one side ora diameter in a case where the aspect ratio is 1) is set to 10 to 100nm, and larger capacity can be realized as the length is as small aspossible in this range. In addition, in the case of this embodiment, themagnetic recording unit 3 is shaped to a circular column shape by usinga photolithography technology after stacking respective layers of themagnetic recording unit 3 on the heavy metal layer 2 by the same methodas in the heavy metal layer 2.

The recording layer 10 of the magnetic recording unit is a ferromagneticfilm formed from a ferromagnetic material. In this embodiment, therecording layer 10 is directly formed on the heavy metal layer 2, and isin contact with the heavy metal layer 2. A material and the thickness ofthe recording layer 10 and the barrier layer 11 to be described laterare selected so that interface magnetic anisotropy occurs in aninterface between the recording layer 10 and the barrier layer 11.Accordingly, the recording layer 10 is magnetized in a verticaldirection with respect to a film surface (hereinafter, simply referredto as “vertical direction”) due to the interface magnetic anisotropyoccurred in the interface between the recording layer 10 and the barrierlayer 11. In FIG. 1A and FIG. 1B, a magnetization M10 of the recordinglayer 10 is indicated by a white blank arrow, and a direction of thearrow indicates a magnetization direction. A situation in which twoarrows of an upward arrow and a downward arrow are drawn in therecording layer 10 represents that a magnetization of the recordinglayer 10 can be reversed. Note that, actually, a component that does notface the magnetization direction (arrow direction) is also included.Hereinafter, this is also true of a case where a magnetization isindicated by an arrow in the drawings of this specification.

As described above, in order to occur the interface magnetic anisotropyin the recording layer 10, the recording layer 10 has a configuration inwhich a CoFeB layer or an FeB layer is disposed at an interface with thebarrier layer 11 of MgO or the like, and a multi-layer film such as aCo/Pt multi-layer film, a Co/Pd multi-layer film, and a Co/Nimulti-layer film which include a Co layer, a regular alloy such asMn—Ga, Mn—Ge, and Fe—Pt, an alloy such as Co—Pt, Co—Pd, Co—Cr—Pt, andCo—Cr—Ta—Pt which contain Co, or the like is inserted between the heavymetal layer 2 and the CoFeB layer or the FeB layer. The number ofstacks, a film thickness, and the like of the multi-layer films and thealloys are appropriately adjusted in correspondence with a size of theMTJ. The barrier layer 11 is preferably formed from an insulator such asMgO, Al₂O₃, AlN, and MgAlO. In addition, the thickness of the recordinglayer 10 is 0.8 to 5.0 nm and preferably 1.0 to 3.0 nm, and thethickness of the barrier layer 11 is 0.1 to 2.5 nm and preferably 0.5 to1.5 nm.

In this embodiment, the recording layer 10 is set to a five-layer filmof amorphous CoFeB (1.5 nm)/Ta (0.4 nm)/Co (0.4 nm)/Pt (0.4 nm)/Co (0.4nm) from the barrier layer 11 side, and the barrier layer 11 is set toMgO (100) (1.0 nm). In the case of using MgO in the barrier layer 11,when forming the recording layer 10 and the barrier layer 11 in thismanner, it is advantageous from the viewpoint that an MR variation rateof the magnetic recording unit 3 can be raised. Note that, the recordinglayer 10 is preferably an amorphous layer. The reason for this is asfollows. When MgO is stacked on an amorphous metal layer, an MgO layerin which a single crystal oriented in a (100) direction is dominant isformed and thus it is easy to form MgO (100) on the recording layer 10due to the characteristic. In addition, an ultrathin film that cutscrystal growth is inserted so as to form an amorphous layer on apolycrystal or single crystal thin film. In this embodiment, Ta (0.4 nm)as the ultrathin film that cuts crystal growth is inserted between CoFeB(1.5 nm) and Co (0.4 nm). The Ta ultrathin film can be changed to anultrathin film of W, Mo, or the like. Here, the layer in which a singlecrystal is dominant represents a crystalline layer having the samedegree of crystallinity as the epitaxial layer formed by epitaxialgrowth. Note that, the configuration of the recording layer 10 can beappropriately changed in correspondence with the material of the heavymetal layer 2. For example, in a case where the heavy metal layer 2 isformed from a W—Ta alloy, the recording layer 10 can be set as one layerof CoFeB (1.5 nm).

The recording layer 10 is magnetized in the vertical direction due tothe interface magnetic anisotropy. However, an easy axis ofmagnetization may be caused to occur in the vertical direction tomagnetize the recording layer 10 in the vertical direction by magneticcrystalline anisotropy or shape magnetic anisotropy. In this case, asthe recording layer 10, for example, an alloy containing at least one ormore of Co, Fe, Ni, and Mn is preferable. Specifically, as an alloycontaining Co, alloys such as Co—Pt, Co—Pd, Co—Cr—Pt, and Co—Cr—Ta—Pt ispreferable, and particularly, it is preferable that the alloys areso-called Co-rich alloys containing Co in a larger amount in comparisonto other elements. As an alloy containing Fe, alloys such as Fe—Pt andFe—Pd are preferable, and particularly, it is preferable that the alloysare so-called Fe-rich alloys containing Fe in a larger amount incomparison to other elements. As an alloy containing Co and Fe, alloyssuch as Co—Fe, Co—Fe—Pt, and Co—Fe—Pd are preferable. The alloycontaining Co and Fe may be Co-rich or Fe-rich. As an alloy containingMn, alloys such as Mn—Ga and Mn—Ge are preferable. In addition, thealloy containing at least one or more kinds of Co, Fe, Ni, and Mn maycontain some elements such as B, C, N, O, P, Al, and Si.

Note that, the recording layer 10 may be a stacked film of aferromagnetic layer formed from the above-described material, and anon-magnetic layer formed from a non-magnetic material such as Ta, W,Mo, Pt, Pd, Ru, Rh, Ir, Cr, Au, Cu, Os, and Re. In a case where therecording layer 10 is set as the stacked film, a layer that is incontact with the heavy metal layer 2 and a layer that is in contact withthe barrier layer 11 are set as a ferromagnetic layer. The recordinglayer 10 may be a stacked film in which a ferromagnetic layer and anon-magnetic layer are alternately stacked, and a layer on the mostheavy metal layer 2 side and a layer on the most barrier layer 11 sideare ferromagnetic layers as in a three-layer stacked film in which afirst ferromagnetic layer, a first non-magnetic layer, and a secondferromagnetic layer are stacked in this order on the heavy metal layer2, a five-layer stacked film in which a first ferromagnetic layer, afirst non-magnetic layer, a second ferromagnetic layer, a secondnon-magnetic layer, and a third ferromagnetic layer are stacked in thisorder on the heavy metal layer 2. Magnetizations of the ferromagneticlayers facing each other with the non-magnetic layer interposedtherebetween may be antiferromagnetically coupled or may beferromagnetically coupled by an interlayer interaction.

The non-magnetic layers (the first non-magnetic layer and the secondnon-magnetic layer) are formed from a non-magnetic metal such as Ir, Rh,Ru, Os, Re, or alloys of these elements, and are formed in a range of0.5 to 1.0 nm or 1.8 to 2.3 nm in the case of Ru, in a range of 0.5 to0.8 nm in the case of Ir, 0.7 to 1.0 nm in the case of Rh, 0.75 to 1.2nm in the case of Os, and in a range of 0.5 to 0.95 nm in the case ofRe. When the ferromagnetic layers (the first ferromagnetic layer and thesecond ferromagnetic layer, or the second ferromagnetic layer and thethird ferromagnetic layer) are stacked through each of the non-magneticlayers having the thickness, magnetizations of the ferromagnetic layersfacing each other with the non-magnetic layer interposed therebetweencan be antiferromagnetically coupled due to the interlayer interaction.A structure in which the ferromagnetic layers and the non-magneticlayers are alternately stacked, and the ferromagnetic layers facing eachother with the non-magnetic layer interposed therebetween areantiferromagnetically coupled due to the interlayer interaction and themagnetization directions are anti-parallel is referred to as a stackedferri structure in this specification.

The interlayer interaction varies in correspondence with the thicknessof the non-magnetic layer between the ferromagnetic layers, and can alsoferromagnetically couple the two ferromagnetic layers. In this case,when the thickness of the non-magnetic layer is made to be smaller orlarger in comparison to a case where the magnetizations of theferromagnetic layers are antiferromagnetically coupled, themagnetizations of the ferromagnetic layers facing each other with thenon-magnetic layer interposed therebetween can be ferromagneticallycoupled due to the interlayer interaction.

In a case where the recording layer 10 is an epitaxial layer or apolycrystal ferromagnetic layer, it is preferable that the recordinglayer 10 is provided with a non-magnetic layer that is formed from Ta,W, Mo, or the like in a thickness of 1 nm or less, and an amorphousferromagnetic layer (approximately 0.6 to 2.0 nm) formed from aferromagnetic material such as CoFeB, FeB, and CoB on a ferromagneticlayer in this order. In this case, the barrier layer 11 formed from MgO(100) is caused to epitaxially grow on the amorphous ferromagneticmaterial, in-plane uniformity in orientation of MgO (100) is improved,and uniformity of resistance variation rate (MR variation rate) can beimproved. In addition, the magnetization of the amorphous ferromagneticlayer is ferromagnetically coupled with the magnetization of theferromagnetic layer that faces the amorphous ferromagnetic layer with anon-magnetic layer interposed therebetween due to the interlayerinteraction, and the magnetizations are directed in the verticaldirection. Note that, the amorphous ferromagnetic layer represents anamorphous layer or a thin film formed from a ferromagnetic material, andalso includes a layer having a crystal in a part in a case whereamorphous is dominant.

The recording layer 10 may be an epitaxial layer formed by epitaxialgrowth. In a case where the recording layer 10 is set as the epitaxiallayer, the barrier layer in which a single crystal is dominant is formedby epitaxially growing the barrier layer 11 on the recording layer 10that is the epitaxial layer, or by separately forming the barrier layer11 that is the epitaxial layer and by laminating the barrier layer 11onto the recording layer 10.

The reference layer 12 is a three-layer stacked film in which aferromagnetic layer 14, a non-magnetic layer 15, and a ferromagneticlayer 16 are stacked on the barrier layer 11 in this order, and has athree-layer stacked ferri structure. Accordingly, a direction of amagnetization M14 of the ferromagnetic layer 14 and a direction of amagnetization M16 of the ferromagnetic layer 16 are anti-parallel, themagnetization M14 is directed to the −z-direction, and the magnetizationM16 is directed to the +z-direction. In this specification, in a casewhere the magnetization directions are anti-parallel, this caserepresents that the magnetization directions are different byapproximately 180°, and it is assumed that a case where a magnetizationis directed in the +z-direction is referred to as upward, and a casewhere the magnetization is directed in the −z-direction is referred toas downward.

In this embodiment, the material and the thickness of the ferromagneticlayer 14 are selected so that the interface magnetic anisotropy occursat an interface between the ferromagnetic layer 14 of the referencelayer 12 on the most barrier layer 11 side and the barrier layer 11, anda magnetization direction of the ferromagnetic layer 14 is set to be thevertical direction. In addition, as described above, the reference layer12 is set as the stacked ferri structure, and the magnetization M14 ofthe ferromagnetic layer 14 and the magnetization M16 of theferromagnetic layer 16 are antiferromagnetically coupled to fix themagnetization M14 and the magnetization M16 in the vertical direction.In this manner, the magnetization of the reference layer 12 is fixed inthe vertical direction. Note that, the direction of the magnetizationM14 and the magnetization M16 may be fixed in the vertical direction byferromagnetically coupling the magnetization M14 of the ferromagneticlayer 14 and the magnetization M16 of the ferromagnetic layer 16 by theinterlayer interaction to fix the magnetization direction.

In this embodiment, the magnetization M14 is fixed downward and themagnetization M16 is fixed upward, but the magnetization M14 may befixed upward and the magnetization M16 may be fixed downward. Inaddition, the direction of the magnetization M14 and the magnetizationM16 may be fixed in the vertical direction by setting the magnetizationdirection of the ferromagnetic layer 14 and the ferromagnetic layer 16to the vertical direction by crystal magnetic anisotropy or shapemagnetic anisotropy, and by antiferromagnetically coupling themagnetization M14 of the ferromagnetic layer 14 and the magnetizationM16 of the ferromagnetic layer 16 by the interlayer interaction to fixthe magnetization direction.

The ferromagnetic layer 14 and the ferromagnetic layer 16 may be formedfrom the same material as in the recording layer 10, and thenon-magnetic layer 15 may be formed from Ir, Rh, Ru, Os, Re, alloys ofthese elements, or the like. The non-magnetic layer 15 is formed in athickness of approximately 0.5 to 1.0 nm in the case of Ru, in athickness of approximately 0.5 to 0.8 nm in the case of Ir, in athickness of approximately 0.7 to 1.0 nm in the case of Rh, in athickness of approximately 0.75 to 1.2 nm in the case of Os, and in athickness of approximately 0.5 to 0.95 in the case of Re. In thisembodiment, the reference layer 12 is configured to include theferromagnetic layer 14: Co—Fe—B (1.5 nm)/Ta (0.4 nm)/Co (0.6 nm)/(Pt(0.8 nm)/Co (0.25 nm))₃/Pt (0.8 nm)/Co (1.0) nm from the barrier layer11 side, the non-magnetic layer 15: Ru (0.85 nm), and the ferromagneticlayer 16: Co 1.0 nm/(Pt 0.8 nm/Co 0.25 nm)₁₃ from the non-magnetic layerside, and the ferromagnetic layer 14 is set to Co—Fe—B to set themagnetization direction of the ferromagnetic layer 14 to the verticaldirection due to the interface magnetic anisotropy. Note that, thenumber “₃” after parentheses in description of “(Pt (0.8 nm)/Co (0.25nm))₃” represents that the two-layer film of Pt (0.8 nm)/Co (0.25 nm) isrepetitively stacked three times (that is, a film of a total of sixlayers). This is also true of “₁₃” in description of “(Pt 0.8 nm/Co 0.25nm)₁₃”.

As described above, the ferromagnetic layer 14 may be a three-layer filmin which an amorphous ferromagnetic layer (approximately 0.6 to 2.0 nm)formed from, for example, Co—Fe—B, Fe—B, Co—B, or the like, anon-magnetic layer (1 nm or less) containing Ta, W, Mo, or the like, anda ferromagnetic layer are sequentially stacked on the barrier layer 11.The amorphous ferromagnetic layer and the ferromagnetic layer of theferromagnetic layer 14 are ferromagnetically coupled due to theinterlayer interaction. For example, the ferromagnetic layer 14 isconfigured like an amorphous ferromagnetic layer: Co—Fe—B (1.5 nm)/anon-magnetic layer: Ta (0.5 nm)/a ferromagnetic layer: a crystallineferromagnetic layer having vertical magnetic anisotropy. In thisconfiguration, a magnetization direction of the amorphous ferromagneticlayer becomes the vertical direction, a magnetization direction of theferromagnetic layer that faces the amorphous ferromagnetic layer withthe non-magnetic layer interposed therebetween also becomes the verticaldirection, and thus a magnetization direction of the ferromagnetic layer14 can be set to the vertical direction.

The insulating layer 5 is provided on a rear surface (a surface of theheavy metal layer 2 which is opposite to the magnetic recording unit 3)of the heavy metal layer 2, which is a surface opposite to the frontsurface of the heavy metal layer 2 on which the magnetic recording unit3 is provided, on a lower side of the magnetic recording unit 3. Theinsulating layer 5 is disposed at a position facing the recording layer10 with the heavy metal layer 2 interposed therebetween, andsubstantially covers a bottom surface (a surface of the magneticrecording unit 3 which is in contact with the heavy metal layer 2) ofthe magnetic recording unit 3. In this embodiment, the insulating layer5 is a circular column-shaped thin film of which a cross-sectional shapecut in an in-plane direction is the same circular shape as in themagnetic recording unit 3, and is disposed so that a central axis of thecircular column-shaped magnetic recording unit 3 and a central axis ofthe circular column-shaped insulating layer 5 overlap each other. Theinsulating layer 5 may cover the entirety of the bottom surface of themagnetic recording unit 3, and it is preferable that the insulatinglayer 5 is manufactured to be slightly larger than a size of therecording layer 10 in consideration of alignment system in processing.

For example, the insulating layer 5 is preferably an insulating filmformed from an insulator with a high dielectric constant(high-dielectric-constant insulator) such as a High-k material, and isprovided on the rear surface of the heavy metal layer 2. Morespecifically, the insulating layer 5 is more preferably formed a High-kmaterial (x>0, y>0) such as AlO_(x), HfSiO_(x), N-added HfSiO_(x),HfAlO_(x), N-added HfAlO_(x), HfO₂Y₂O₃, HfO_(x), and LaAlO_(x). Inaddition, it is preferable that the insulating layer 5 is formed from aHigh-k material but may be formed from a typical insulator such asSiO_(x), SiN_(x), and SiO_(x)N_(y) (x>0, y>0). A relative dielectricconstant of the insulator with a high dielectric constant isapproximately 10 to 30.

It is preferable that the thickness of the insulating layer 5 is set toa thickness at which a tunnel current or a leak current does not flow tothe insulating layer 5 or the insulating layer 5 is not subjected toinsulation breakdown when a voltage is applied to the heavy metal layer2 from a first terminal T1 to be described later through the insulatinglayer 5. The thickness of the insulating layer 5 also depends on amaterial that is used or an applied voltage. However, the thickness ispreferably about 1.5 nm or more and 100 nm or less, and more preferably2.0 nm or more 10 nm or less. Note that, in this embodiment, theinsulating layer 5 is formed as a two-layer film of HfO_(x)/SiO_(x) fromthe heavy metal layer 2 side, and the thickness thereof is set to 2 nmand 1 nm, respectively. In this manner, since the magnetoresistanceeffect element 1 includes the insulating layer 5 on the rear surface ofthe heavy metal layer 2, it is possible to apply a voltage to the heavymetal layer 2 between the insulating layer 5 and the magnetic recordingunit 3 by applying a voltage to the insulating layer 5, and it ispossible to cause an electric field to occur. If a desired electricfield can be applied to the heavy metal layer 2, when the film thicknessof the insulating layer 5 is as thin as possible in a range in which thetunnel current or the leak current does not flow to the insulating layer5 or the insulating layer 5 is not subjected to the insulationbreakdown, an application voltage can be reduced, and power consumptioncan be reduced.

The insulating layer 5 is manufactured by depositing an insulator on abase layer or a circuit substrate by a typical film formation methodsuch as CVD, and shaping the insulator to a desired shape (a circularcolumn shape in this embodiment) by a lithography technology. In a casewhere the first terminal T1 is provided, for example, Cu is depositedand the insulator is subsequently deposited, and then the first terminalT1 and the insulating layer 5 are shaped by lithography or the like. Forexample, the insulating layer 5 is formed on a drain terminal wiring ofa transistor on the circuit substrate into which an FET-type transistoris embedded. In addition, the heavy metal layer 2 and the magneticrecording unit 3 are formed on the insulating layer 5. Actually, aftershaping the insulating layer 5, an interlayer insulating film having thesame height as that of the insulating layer 5 is formed at the peripheryof the insulating layer 5, a planarization treatment is performed, andthe heavy metal layer 2 is formed.

Four terminals (the first terminal T1, a second terminal T2, a thirdterminal T3, and a fourth terminal T4), from which a voltage is appliedor a current flows for a write operation or a read operation, areconnected to the magnetoresistance effect element 1. Themagnetoresistance effect element 1 is a four-terminal element. The firstterminal T1, the second terminal T2, the third terminal T3, and thefourth terminal T4 are members formed from a metal such as Cu, Al, andAu which have conductivity, and the shape thereof is not particularlylimited.

The first terminal T1 is provided in contact with the insulating layer 5on a lower side of the insulating layer 5, that is, at a position facingthe magnetic recording unit 3 with the insulating layer 5 and the heavymetal layer 2 interposed therebetween. In this embodiment, the firstterminal T1 is a circular column-shaped thin film of which across-sectional shape cut in the in-plane direction is the same circularshape as in the insulating layer 5, and is disposed on a surface of theinsulating layer 5, which is on a rear side of a surface that is incontact with the heavy metal layer 2, to cover the entirety of the rearsurface. In addition, in this embodiment, an FET-type first transistorTr1 is connected to the first terminal T1. In the first transistor Tr1,a drain is connected to the first terminal T1, a source is connected toa write bit line (not illustrated), and a gate is connected to a controldevice (not illustrated). The control device applies a gate voltage tothe gate of the first transistor Tr1, and controls ON and OFF of thefirst transistor Tr1. The write bit line is also connected to thecontrol device, and thus the control device controls a voltage level ofthe write bit line. A voltage level of the write bit line is set toV_(Assist), and when the first transistor Tr1 is turned on, a writeassist voltage V_(Assist) for reversing the magnetization M10 of therecording layer 10 of the magnetic recording unit is applied to theheavy metal layer 2 through the insulating layer 5. In this manner, thefirst terminal T1 is connected to the insulating layer 5, and applies avoltage to the heavy metal layer 2 through the insulating layer 5.

The second terminal T2 is provided on the reference layer 12 of themagnetic recording unit 3 in contact with the reference layer 12 (theferromagnetic layer 16 thereof), and is connected to the reference layer12. In this embodiment, the second terminal T2 is a circularcolumn-shaped thin film of which a cross-sectional shape cut in thein-plane direction is the same circular shape as in the magneticrecording unit 3, and is disposed on an upper surface of the magneticrecording unit 3 to cover the entirety of the upper surface. Inaddition, in this embodiment, an FET-type second transistor Tr2 isconnected to the second terminal T2. In the second transistor Tr2, adrain is connected to the second terminal T2, a source is connected to aread bit line (not illustrated), and a gate is connected to the controldevice. The control device applies a gate voltage to the gate of thesecond transistor Tr2, and controls ON and OFF of the second transistorTr2. A read bit line is also connected to the control device, and thecontrol device controls a voltage level of the read bit line. A voltagelevel of the read bit line is set to V_(Read), and when the secondtransistor Tr2 is turned on, a read voltage V_(Read) is applied to thesecond terminal T2.

The third terminal T3 and the fourth terminal 14 are provided in one endand in the other end of the heavy metal layer 2 so that the magneticrecording unit 3 is disposed between the both terminals. In thisembodiment, the third terminal T3 is provided on a surface of the oneend of the heavy metal layer 2 in a first direction, and the fourthterminal T4 is provided on a surface of the other end of the heavy metallayer 2 in the first direction. The third terminal T3 is connected to anFET-type third transistor Tr3, and the fourth terminal T4 is connectedto a ground. In the third transistor Tr3, a drain is connected to thethird terminal T3, a source is connected to a control line (notillustrated), and a gate is connected to the control device. The controldevice applies a gate voltage to the gate of the third transistor Tr3,and controls ON and OFF of the third transistor Tr3. A control line isalso connected to the control device, and the control device controls avoltage level of the control line.

The voltage level of the control line is set to V_(W), and when thethird transistor Tr3 is turned on, a write voltage V_(W) is applied tothe third terminal T3, and a write current Iw flows between the thirdterminal T3 and the fourth terminal T4 in the first direction. In thismanner, the third terminal T3 and the fourth terminal T4 are connectedto the heavy metal layer 2 (one end and the other end thereof), andallow the write current Iw to flow to the heavy metal layer 2 betweenthe magnetic recording unit 3 and the insulating layer 5. In addition,when the second transistor Tr2 and the third transistor Tr3 are turnedon, a read current Ir for reading a resistance value of the magneticrecording unit 3 flows between the second terminal T2 and the thirdterminal T3 in correspondence with a potential difference of the secondterminal T2 and the third terminal T3. In this embodiment, since V_(W)is set to be higher than V_(Read), the read current Ir can be caused toflow to the second terminal T2 from the third terminal T3 through theheavy metal layer 2 and the magnetic recording unit 3.

As described above, in this embodiment, the third terminal T3 and thefourth terminal T4 are provided on the front surface (surface on whichthe magnetic recording unit 3 is provided) of the heavy metal layer 2,and contact from an upper side to the magnetoresistance effect element 1is made, but there is no limitation thereto. For example, the thirdterminal T3 and the fourth terminal 14 may be provided on the rearsurface (surface on a rear side of the surface on which the magneticrecording unit 3 is provided) of the heavy metal layer 2, and contactfrom a lower side to the magnetoresistance effect element 1 may be made.

(1-2) Write Method and Read Method for Magnetoresistance Effect Element

Description will be given of a write method for the magnetoresistanceeffect element 1 with reference to FIG. 2A, FIG. 2B, FIG. 2C, and FIG.2D in which the same reference numeral is given to the sameconfiguration as in FIG. 1A and FIG. 1B. In the magnetoresistance effectelement 1, resistance of the magnetic recording unit 3 varies dependingon whether magnetization directions of the recording layer 10 and thereference layer 12 are parallel or anti-parallel. Actually, in themagnetoresistance effect element 1, since the reference layer 12 is astacked film, the resistance of the magnetic recording unit 3 variesdepending on whether the magnetization direction of the recording layer10 and the magnetization direction of the ferromagnetic layer 14 of thereference layer 12 which is in contact with the barrier layer 11 areparallel or anti-parallel. In addition, in a case where the recordinglayer 10 is also a stacked film, the resistance of the magneticrecording unit 3 varies depending on whether the magnetization directionof the ferromagnetic layer of the recording layer 10 which is in contactwith the barrier layer 11, and the magnetization direction of theferromagnetic layer 14 of the reference layer 12 which is in contactwith the barrier layer 11 are parallel or anti-parallel.

In this specification, in a case where the recording layer 10 and thereference layer 12 are in a parallel state, it is assumed that this casealso include a state in which the magnetization direction of theferromagnetic layer of the recording layer 10 which is in contact withthe barrier layer 11, and the magnetization direction of theferromagnetic layer 14 of the reference layer 12 which is in contactwith the barrier layer 11 are parallel in a stacked film of therecording layer 10 and the reference layer 12. In addition, in a casewhere the recording layer 10 and the reference layer 12 are in ananti-parallel state, it is assumed that this case indicates a state inwhich the magnetization direction of the ferromagnetic layer of therecording layer 10 which is in contact with the barrier layer 11, andthe magnetization direction of the ferromagnetic layer 14 of thereference layer 12 which is in contact with the barrier layer 11 areanti-parallel in the stacked film of the recording layer 10 and thereference layer 12.

In the magnetoresistance effect element 1, one-bit data of “0” andone-bit data of “1” are allocated to the parallel state and theanti-parallel state, respectively, by using a situation in which aresistance value of the magnetic recording unit 3 is different betweenthe parallel state and the anti-parallel state, thereby storing data inthe magnetoresistance effect element 1. In the magnetoresistance effectelement 1, since the magnetization direction of the recording layer 10is reversible, the magnetization direction of the recording layer 10 isreversed to transition the magnetization state of the magnetic recordingunit 3 between the parallel state and the anti-parallel state. Accordingto this, “1” is stored in the magnetic recording unit 3 (hereinafter,also referred to as “bit”) that stored “0”, and “0” is stored in a bitthat stored “1”. In this specification, a statement in which theresistance value of the magnetic recording unit 3 is changed throughreversal of the magnetization direction of the recording layer 10 isalso referred to as “data is written”.

The write method for the magnetoresistance effect element 1 will bedescribed in more detail. In this embodiment, the heavy metal layer 2 isformed from Pt—Au in which the sign of the spin hall angle is positive.Here, description will be given of an example in which the spin hallangle of the heavy metal layer 2 is positive. In a case where the spinhall angle of the heavy metal layer 2 is negative, it is possible tocontrol a spin direction of the recording layer 10 by either reversing adirection of the following write current Iw or reversing a sign of awrite assist voltage V_(Assist). Description will be given of a casewhere data “0” is written to magnetoresistance effect element 1 that isstoring data “1”.

In this case, it is assumed that in an initial state, themagnetoresistance effect element 1 is storing data “1”, a magnetizationdirection of the recording layer 10 is upward, a magnetization directionof the ferromagnetic layer 14 of the reference layer 12 which is incontact with the barrier layer 11 is downward, and the magneticrecording unit 3 is in an anti-parallel state. In addition, it isassumed that the first transistor Tr1, the second transistor Tr2, andthe third transistor Tr3 are turned off.

First, as illustrated in FIG. 2A, the magnetoresistance effect element 1turns on only the first transistor Tr1, and a positive write assistvoltage V_(Assist) is applied from the first terminal T1 to the heavymetal layer 2 through the insulating layer 5. As a result, an electricfield in the −z-direction occurs in the heavy metal layer 2. Themagnitude of the write assist voltage V_(Assist) is appropriatelyadjusted in correspondence with a material or the thickness of theinsulating layer 5, and the magnitude of the write current Iw. In thisembodiment, the insulating layer 5 is formed in a two-layer film ofHfO_(x) (2 nm)/SiO_(x) (1 nm), and thus the write assist voltageV_(Assist) is set to, for example, 1.5 V. Note that, at this time, sincethe second transistor Tr2 is turned off, even when a voltage is appliedto the heavy metal layer 2 through the insulating layer 5, the voltageis not applied to the barrier layer 11.

Next, as illustrated in FIG. 2B (in FIG. 2B, a magnetization directionof the recording layer 10 after writing is illustrated), the firsttransistor Tr1 is retained to the ON state, the third transistor Tr3 isturned on, and a write voltage V_(W) is applied to the third terminalT3. At this time, since the write voltage V_(W) is set to be higher thana ground voltage, the write current Iw flows from the third terminal T3to the fourth terminal 14 through the heavy metal layer 2, and the writecurrent Iw flows from one end of the heavy metal layer 2 to the otherend in the +x-direction. Since the insulating layer 5 is provided, thecurrent does not flow from the third terminal T3 to the first terminalT1. In addition, since the second transistor Tr2 is turned off, thecurrent also does not flow from the third terminal T3 to the secondterminal T2 through the magnetic recording unit 3. In this embodiment,the write current Iw flows between the one end and the other end of theheavy metal layer 2. The write current Iw is a pulse current, and apulse width can be changed by adjusting time for which the thirdtransistor Tr3 is turned on.

When the write current Iw flows to the heavy metal layer 2, a spincurrent (spin angular motion current) occurs in the heavy metal layer 2due to a spin hall effect by a spin orbit interaction, and spinsdirected to a paper-surface front side (−y-direction in FIG. 1A) flow tothe upper surface side (+z-direction) of the heavy metal layer 2, spinswhich are anti-parallel to the spins in a direction and are directed toa paper surface depth side (+y-direction in FIG. 1A) flow to the lowersurface side (−z-direction) of the heavy metal layer 2, and the spinsare unevenly distributed in the heavy metal layer 2.

At this time, in the heavy metal layer 2 interposed between theinsulating layer 5 and the recording layer 10, an electric field in the−z-direction occurs and electrons flow in the −x-direction, and thus aneffective magnetic field occurs due to a Rashba effect, and spins whichare unevenly distributed perform precessional motion due to theeffective magnetic field. When the spins having performed theprecessional motion flow into the recording layer 10 due to the spincurrent flowing through the heavy metal layer 2, the magnetization M10of the recording layer 10 is likely to be reversed to a predetermineddirection, and an upward magnetization M10 is reversed to downward dueto torque from the spins having performed the processional motion, andit enters a parallel state. In this manner, when a voltage is applied tothe heavy metal layer 2 through the insulating layer 5 and the writecurrent Iw flows to the heavy metal layer 2, the magnetization of therecording layer 10 is reversed. The first transistor Tr1 is turned offafter the third transistor Tr3 is turned off. That is, after the writecurrent Iw is set to OFF, application of the write assist voltageV_(Assist) is set to OFF.

Next, description will be given of a case where data “1” is written tothe magnetoresistance effect element 1 that is storing data “0”.

In this case, it is assumed that in an initial state, themagnetoresistance effect element 1 is storing data “1”, a magnetizationdirection of the recording layer 10 is downward, a magnetizationdirection of the ferromagnetic layer 14 of the reference layer 12 whichis in contact with the barrier layer 11 is downward, and the magneticrecording unit 3 is in a parallel state. In addition, it is assumed thatthe first transistor Tr1, the second transistor Tr2, and the thirdtransistor Tr3 are turned off.

First, as illustrated in FIG. 2C, only the first transistor Tr1 isturned on, and a negative write assist voltage V_(Assist) is appliedfrom the first terminal T1 to the heavy metal layer 2 through theinsulating layer 5. As a result, an electric field in the +z-directionoccurs in the heavy metal layer 2.

Next, as illustrated in FIG. 2D (in FIG. 2D, a magnetization directionof the recording layer 10 after writing is illustrated), the firsttransistor Tr1 is retained to the ON state, the third transistor Tr3 isturned on, and the write voltage V_(W) is applied to the third terminalT3. At this time, since the write voltage V_(W) is set to be higher thana ground voltage, the write current Iw flows from the third terminal T3to the fourth terminal 14 through the heavy metal layer 2, and the writecurrent Iw flows from one end of the heavy metal layer 2 to the otherend in the +x-direction.

When the write current Iw flows to the heavy metal layer 2, a spincurrent (spin angular motion current) occurs in the heavy metal layer 2due to a spin hall effect by a spin orbit interaction, and spinsdirected to a paper-surface front side (−y-direction in FIG. 1A) flow tothe upper surface side (+z-direction) of the heavy metal layer 2, spinswhich are anti-parallel to the spins in a direction and are directed toa paper surface depth side (+y-direction in FIG. 1A) flow to the lowersurface side (−z-direction) of the heavy metal layer 2, and the spinsare unevenly distributed in the heavy metal layer 2.

At this time, in the heavy metal layer 2 interposed between theinsulating layer 5 and the recording layer 10, an electric field in the+z-direction occurs and electrons flow in the −x-direction, and thus aneffective magnetic field occurs due to a Rashba effect, and spins whichare unevenly distributed due to the effective magnetic field performprecessional motion. When the spins having performed the precessionalmotion flow into the recording layer 10 due to the spin current flowingthrough the heavy metal layer 2, the magnetization M10 of the recordinglayer 10 is likely to be reversed to a predetermined direction, and adownward magnetization M10 is reversed to upward due to torque from thespins having performed the processional motion, and it enters ananti-parallel state. In addition, the first transistor Tr1 is turned offafter the third transistor Tr3 is turned off. That is, after the writecurrent Iw is set to OFF, application of the write assist voltageV_(Assist) is set to OFF.

In this manner, in the magnetoresistance effect element 1, the voltageis applied to the heavy metal layer 2 through the insulating layer 5,and the write current Iw flows between the one end and the other end ofthe heavy metal layer 2, and thus the magnetization direction of therecording layer 10 of the magnetic recording unit 3 is reversed, anddata “0” or data “1” can be written.

In an SOT-MRAM element in the related art, a voltage is applied to oneend and the other end of a heavy metal layer, a write current is causedto flow to the heave metal layer, and a voltage is applied to an MTJ toreduce magnetic anisotropy of a recording layer. According to this,magnetization of the recording layer is reversed due to spins injectedfrom the heavy metal layer. According to this, a current flows to theMTJ in writing. On the other hand, in the magnetoresistance effectelement 1 of this embodiment, in a write operation, the secondtransistor Tr2 is always turned off, and thus a voltage is not appliedto the MTJ of the magnetic recording unit 3, and a current also does notflow to the MTJ. In addition, in the magnetoresistance effect element 1,even when a voltage is applied to the heavy metal layer 2 through theinsulating layer 5, a voltage is not applied to the barrier layer 11.

As described above, in the magnetoresistance effect element 1, eventhough a voltage is not applied to the magnetic recording unit 3 forwriting data differently from the magnetoresistance effect element inthe related art, a voltage is applied to the heavy metal layer 2 throughthe insulating layer 5 and the write current Iw is caused to flow to theheavy metal layer 2, and thus the magnetization of the recording layer10 of the magnetic recording unit 3 can be reversed. According to this,in the magnetoresistance effect element 1, in writing, since a voltageis not applied to the barrier layer 11 of the magnetic recording unit 3and a current also does not flow thereto, the resistance value of themagnetic recording unit 3 can be made small by reducing the thickness ofthe barrier layer 11, time necessary for a write operation can beshortened, and high speed of the magnetoresistance effect element 1 canbe realized.

In the SOT-MRAM element in the related art, in the case of using the MTJin which the recording layer and the barrier layer are magnetizedvertically with respect to an in-plane direction, if an externalmagnetic field is not applied to the MTJ by preparing a magnetic fieldapplication device or the like, the magnetization of the recording layercannot be reversed, and data cannot be written. On the other hand, inthe magnetoresistance effect element 1 of this embodiment, the writecurrent Iw is caused to flow to the heavy metal layer 2, a voltage isapplied to the heavy metal layer 2 through the insulating layer 5, spinsunevenly distributed is caused to perform precessional motion due to theeffective magnetic field occurred by the Rashba effect, and the spinsperforming the precessional motion are injected to the recording layer10 by the spin current. According to this, the magnetization of therecording layer 10 that is magnetized in the vertical direction can bereversed due to the spins having performed the precession motion, andthus the magnetization of the recording layer 10 can be reversed withoutapplying an external magnetic field, and data can be written. Inaddition, it is not necessary to prepare the magnetic field applicationdevice, and thus space saving can be realized.

Next, a read method will be described with reference to FIG. 3. At thistime, it is assumed that in an initial state, all transistors are turnedon. In reading, the second transistor and the third transistor areturned on, a read voltage V_(Read) is applied to the second terminal T2,and the write voltage V_(W) is applied to the third terminal T3. At thistime, since the read voltage V_(Read) is set to be lower than the writevoltage V_(W), the read current Ir flows from the third terminal T3 tothe heavy metal layer 2, the recording layer 10, the barrier layer 11,the reference layer 12, and the second terminal T2 in this order. Themagnitude of the read current Ir varies depending on the resistancevalue of the magnetic recording unit 3, and thus a situation as towhether the magnetic recording unit 3 is in a parallel state or ananti-parallel state, that is, whether the magnetic recording unit 3 isstoring data “0” or data “1” can be read from the magnitude of the readcurrent Ir. The read current Ir is a pulse current, and a pulse width isadjusted by adjusting time for which the second transistor Tr2 is turnedon.

It is preferable that the read current Ir is set to a weak current to acertain extent in which the recording layer 10 is not subjected to spininjection magnetization reversal due to the read current Ir when theread current Ir flows to the magnetic recording unit 3. The magnitude ofthe read current Ir is adjusted by appropriately adjusting a potentialdifference between the write voltage V_(W) and the read voltageV_(Read). In addition, it is preferable that the third transistor Tr3 isturned on to set the write voltage V_(W) to ON, and then the secondtransistor Tr2 is turned on to set the read voltage V_(Read) to ON. Inthis case, it is possible to suppress a current from flowing to thefourth terminal T4 from the second terminal T2 through the magneticrecording unit 3, and it is possible to suppress a current other thanthe read current from flowing to the magnetic recording unit 3.

Then, the second transistor Tr2 is turned off, and then the thirdtransistor Tr3 is turned off. Since the third transistor Tr3 is turnedoff after the second transistor Tr2, that is, the write voltage V_(W) isset to OFF after the read voltage V_(Read), it is possible to suppress acurrent corresponding to a potential difference between the read voltageV_(Read) and the ground voltage from flowing from the second terminal T2to the fourth terminal T4 through the magnetic recording unit 3 and theheavy metal layer 2. Accordingly, in the magnetoresistance effectelement 1, the barrier layer 11 can be protected, the barrier layer 11can also be made thin, and it is possible to suppress Read disturb inwhich a magnetization state of the recording layer 10 is changed due tocurrent flowing through the magnetic recording unit 3.

As described above, in the magnetoresistance effect element 1, thevoltage V_(Assist) is applied to the first terminal T1 in writing, theread voltage V_(Read) is applied to the second terminal T2 in reading, avoltage control line in writing and a voltage control line in readingare different from each other, and thus it is possible to construct aRead disturb free and Write disturb free memory array.

In the magnetoresistance effect element 1, a sign of the write assistvoltage V_(Assist) and a direction in which the write current Iw iscaused to flow vary depending on the magnetization direction of therecording layer 10 (a magnetization direction of the ferromagnetic layerthat is in contact with the heavy metal layer in a case where therecording layer 10 is a stacked film). In a case where the magnetizationM10 of the recording layer 10 is upward, the write assist voltageV_(Assist) is set to positive, and the write current Iw is caused toflow in the +x-direction, thereby reversing the upward magnetization M10to downward. In addition, in a case where the magnetization M10 of therecording layer 10 is downward, the write assist voltage V_(Assist) isset to negative, and the write current Iw is caused to flow in the+x-direction, thereby reversing the downward magnetization M10 toupward.

On the other hand, in a case where the magnetization M10 of therecording layer 10 is upward, as illustrated in FIG. 4A and FIG. 4B(FIG. 4A illustrates a magnetization direction of the recording layer 10before writing, and FIG. 4B illustrates a magnetization direction of therecording layer 10 after writing) in which the same reference numeral isgiven to the same configuration as in FIG. 2A and FIG. 2B, even in acase where the sign of the write assist voltage V_(Assist) is set tonegative, a negative voltage is applied to the heavy metal layer 2, andthe write current Iw is caused to flow in the −x-direction, the upwardmagnetization M10 can be reversed to downward.

In a case where the magnetization M10 is downward, as illustrated inFIG. 4C and FIG. 4D (FIG. 4C illustrates a magnetization directionbefore writing, and FIG. 4D illustrates a magnetization direction afterwriting) in which the same reference numeral is given to the sameconfiguration as in FIG. 2A and FIG. 2B, when the sign of the writeassist voltage V_(Assist) is set to positive, a positive voltage isapplied to the heavy metal layer 2, and the write current Iw is causedto flow in the −x-direction, the downward magnetization M10 can bereversed to upward.

In a case where the sign of the spin hall angle of a materialconstituting the heavy metal layer 2 is negative, in the respectivecases, when any one of the sign of the write assist voltage V_(Assist)and the direction in which the write current Iw is caused to flow is setto opposite, the magnetization of the recording layer 10 can bereversed. For example, in the case in FIG. 2A and FIG. 2B, the sign ofthe write assist voltage V_(Assist) is set to negative, a negativevoltage is applied to the heavy metal layer 2, and the write current Iwis caused to flow in the +x-direction, thereby reversing the upwardmagnetization M10 to downward.

(1-3) Modification Example of Magnetoresistance Effect Element ofEmbodiment of Invention

In the above-described embodiment, description has been given of a casewhere the cross-sectional shape of the insulating layer 5 is set to thesame circular shape as in the magnetic recording unit 3, and theinsulating layer 5 covers the entirety of the bottom surface of themagnetic recording unit 3 on the rear surface of the heavy metal layer2, but the invention is not limited to this case. A shape of theinsulating layer 5 is not particularly limited as long as the insulatinglayer 5 can substantially cover the bottom surface of the magneticrecording unit 3 from the rear surface side of the heavy metal layer 2,and may be various shapes such as a triangular shape, a quadrangularshape, a polygonal shape of a quadrangle or greater, and an ellipticalshape. In addition, in the insulating layer 5, a cross-sectional area inthe in-plane direction may be larger than a cross-sectional area of themagnetic recording unit 3. For example, as in a magnetoresistance effectelement 1 a illustrated in FIG. 5A, a cross-sectional shape of aninsulating layer 51 in the in-plane direction may be set to the sameshape as in the heavy metal layer 2, and the insulating layer 51 maycover the entirety of a rear surface of the heavy metal layer 2. In thiscase, the insulating layer 51 and the heavy metal layer 2 can becontinuously stacked, and a process of shaping the insulating layer to,for example, a circular column shape or the like can be omitted, andthus the magnetoresistance effect element can be manufactured in aneasier manner.

As in a magnetoresistance effect element 1 b illustrated in FIG. 5B, adiode 17 c may be provided on the ferromagnetic layer 16 of thereference layer 12. In the diode 17 c, an anode side is in contact withthe ferromagnetic layer 16, and a cathode side is in contact with thesecond terminal T2, and thus a current is suppressed from flowing fromthe second terminal T2 to the heavy metal layer 2. In this case, in theread operation, since the read voltage V_(Read) is higher than theground voltage, the current is suppressed from flowing from the secondterminal T2 to the fourth terminal 14 through the magnetic recordingunit 3 and the heavy metal layer 2, and only the read current Ir can becaused to flow to the magnetic recording unit 3, and thus the thicknessof the barrier layer 11 can be made smaller. Note that, a configurationof the diode 17 c is not particularly limited. For example, the diode 17c may be a PN junction in which a P-type semiconductor layer and anN-type semiconductor layer are sequentially stacked on the ferromagneticlayer 16.

As in a magnetoresistance effect element 1 c illustrated in FIG. 5C, itis possible to employ a configuration in which the second terminal T2,the magnetic recording unit 3, the heavy metal layer 2, the insulatinglayer 5, and the first terminal T1 are sequentially stacked on a circuitsubstrate (not illustrated), and the magnetic recording unit 3 isdisposed on a lower side of the insulating layer 5 with the heavy metallayer 2 interposed therebetween. Even in this case, the recording layer10 of the magnetic recording unit 3 is set to be in contact with theheavy metal layer 2.

In the embodiment, description has been given of a case where thecross-sectional area of the insulating layer 5 and the first terminal T1in the in-plane direction is set to be the same as the cross-sectionalarea of the magnetic recording unit 3 in the in-plane direction asillustrated in FIG. 1B, but there is no limitation to this case. Forexample, as in a magnetoresistance effect element 1 d illustrated inFIG. 5D, a cross-sectional area of an insulating layer 55 and a firstterminal T1 d in the in-plane direction may be set to be greater than across-sectional area of the magnetic recording unit 3 in the in-planedirection. In this manner, in a magnetoresistance effect element, it ispreferable that the cross-sectional area of the insulating layer 5 andthe first terminal T1 in the in-plane direction is set to be greaterthan the cross-sectional area of the magnetic recording unit 3 in thein-plane direction, and a voltage is applied to the entirety of a lowerportion of the magnetic recording unit 3. However, the cross-sectionalarea of the insulating layer 5 and the first terminal T1 in the in-planedirection may be set to be smaller than the cross-sectional area of themagnetic recording unit 3 in the in-plane direction. In addition, theinsulating layer, the first terminal, and the magnetic recording unitmay be formed in various columnar shapes such as a prism shape insteadof the circular column shape. This is also true of the second terminalT2 formed in the same cross-sectional shape as in the magnetic recordingunit 3.

In the embodiment, description has been given of a case where thecross-sectional shape of the insulating layer 5 and the first terminalT1, and the cross-sectional shape of the magnetic recording unit 3 havethe same shape and the same size, and the central axis of the magneticrecording unit 3, and the central axis of the insulating layer 5 and thefirst terminal T1 are arranged to overlap each other (a case where themagnetic recording unit 3, the insulating layer 5, and the firstterminal T1 have a flush structure in self-alignment), but the inventionis not limited to this case. For example, as in a magnetoresistanceeffect element 1 e illustrated in FIG. 5E, it is possible to employ aconfiguration in which the cross-sectional area of the insulating layer55 and the first terminal T1 d in the in-plane direction is set to begreater than the cross-sectional area of the magnetic recording unit 3in the in-plane direction, an end position of one of the insulatinglayer 55 and the first terminal T1 d is disposed at approximately thesame position on a straight line as in an end position of the magneticrecording unit 3, and a formation position of the magnetic recordingunit 3, and a formation position of the insulating layer 5 and the firstterminal T1 deviate from each other. That is, it is possible to employ astructure in which the central axis of the magnetic recording unit 3 andthe central axis of the insulating layer 55 and the first terminal T1 ddeviate from each other, and the magnetic recording unit 3, and theinsulating layer 55 and the first terminal T1 d do not have the flushstructure in the self-alignment. In this manner, in themagnetoresistance effect element 1 e, even though positional deviationof the central axis is present between the insulating layer 55 and thefirst terminal T1 d, and the magnetic recording unit 3, since theinsulating layer 55 covers the entirety of the bottom portion of themagnetic recording unit 3, a voltage can be applied to the entirety ofthe lower portion of the magnetic recording unit 3.

As in a magnetoresistance effect element if illustrated in FIG. 5F, itis possible to employ a configuration in which the cross-sectional shapeof the insulating layer 5 and the first terminal T1, and thecross-sectional shape of the magnetic recording unit 3 are set to thesame shape and the same size, and a position of the central axis of themagnetic recording unit 3, and a position of the central axis of theinsulating layer 5 and the first terminal T1 deviate from each other.That is, both end positions of the insulating layer 5 and the firstterminal T1, and both end positions of the magnetic recording unit 3 arenot located on the same straight line, the insulating layer 5 does notcover the entirety of the bottom portion of the magnetic recording unit3, and covers a partial region thereof. In this manner, even though themagnetic recording unit 3, and the insulating layer 55 and the firstterminal T1 d do not have the flush structure in the self-alignment, avoltage can be applied to the lower portion of the magnetic recordingunit 3.

As in a magnetoresistance effect element 1 g illustrated in FIG. 5G, themagnetic recording unit 3 and the first terminal T1 may not be flushedwith each other in the self-alignment also in a case where across-sectional shape of an insulating layer 51 in the in-planedirection is the same shape as in the heavy metal layer 2, and theinsulating layer 51 completely covers the rear surface of the heavymetal layer 2. In addition, a magnetic recording unit 22, and theinsulating layer 5 and the first terminal T1 may not have the flushstructure in the self-alignment also in a magnetoresistance effectelement 1 h including a diode 17 c on the ferromagnetic layer 16 of thereference layer 12 as illustrated in FIG. 5H. In addition, also in amagnetoresistance effect element 1 i having a configuration in which themagnetic recording unit 3 is disposed on the lower portion of theinsulating layer 5 with the heavy metal layer 2 interposed therebetweenas illustrated in FIG. 5I, the magnetic recording unit 3, and theinsulating layer 5 and the first terminal T1 may not have the flushstructure in the self-alignment.

In the embodiment, description has been given of a case where data isstored by associating the resistance value of the magnetic recordingunit 3 in the anti-parallel state with data “1”, and by associating theresistance value in the parallel state with “0”, but the invention isnot limited to this case. For example, data may be stored by associatingthe resistance value of the magnetic recording unit 3 in theanti-parallel state with data “0”, and by associating the resistancevalue in the parallel state with “1”.

In the embodiment, description has been given of a case where the firsttransistor Tr1 is turned on to apply a voltage to the heavy metal layer2 through the insulating layer 5, and then, the third transistor Tr3 isturned on to cause the write current Iw to flow to the heavy metal layer2, thereby reversing the magnetization direction of the recording layer10 of the magnetic recording unit 3, but the invention is not limited tothis case. For example, the first transistor Tr1 and the thirdtransistor Tr3 may be simultaneously turned on, and voltage applicationto the heavy metal layer 2 and flowing of the write current Iw to theheavy metal layer 2 may be simultaneously performed. In addition, themagnetization direction of the recording layer 10 of the magneticrecording unit 3 may be reversed by turning on the third transistor Tr3to cause the write current Iw to flow to the heavy metal layer 2, andthen by turning on the first transistor Tr1 to apply a voltage to theheavy metal layer 2. In this manner, timing at which the firsttransistor Tr1 and the third transistor Tr3 are turned on is notparticularly limited, but it is preferable that the third transistor Tr3is turned on after the first transistor Tr1 is turned on from theviewpoint that write error rate (WER) can be reduced.

In the embodiment, description has been given of a case where the thirdtransistor Tr3 is turned off to set the write current Iw to OFF, andthen the first transistor Tr1 is turned off to set a voltage applied tothe heavy metal layer 2 through the insulating layer 5 to OFF, but theinvention is not limited to this case. For example, the first transistorTr1 and the third transistor Tr3 may be simultaneously turned off tosimultaneously set the write current Iw and the voltage application tothe heavy metal layer 2 to OFF. In addition, after the first transistorTr1 is turned off to set the voltage application to the heavy metallayer 2 to OFF, the third transistor Tr3 may be turned off to set thewrite current Iw to OFF. In this manner, timing at which the firsttransistor Tr1 and the third transistor Tr3 are turned off in writing isnot particularly limited, but it is preferable that the first transistorTr1 is turned off after the third transistor Tr3 is turned off from theviewpoint that the WER can be reduced.

In the embodiment, description has been given of a case where the secondtransistor Tr2 and the third transistor Tr3 are turned on to cause theread current Ir to flow from the third terminal T3 to the heavy metallayer 2, the magnetic recording unit 3, and the second terminal T2, butthe invention is not limited to this case. The read current Ir may becaused to flow from the second terminal T2 to the magnetic recordingunit 3, the heavy metal layer 2, and the fourth terminal T4 by turningon only the second transistor Tr2. In addition, the read voltageV_(Read) may be set to be smaller than the ground voltage, and only thesecond transistor Tr2 may be turned on to cause the read current Ir toflow from the ground to the fourth terminal T4, the heavy metal layer 2,the magnetic recording unit 3, and the second terminal T2.

In the embodiment, description has been given of a case where the fourthterminal 14 is directly connected to the ground, but the invention isnot limited to this case. For example, a drain of a fourth transistormay be connected to the fourth terminal T4, a source of the fourthtransistor may be connected to a wiring to the ground, and the fourthterminal and the ground may be connected through the transistor.

(1-4) Operation and Effect

In the above-described configuration, the magnetoresistance effectelement 1 includes the heave metal layer 2; the magnetic recording unit3 including the recording layer 10 that includes a ferromagnetic layerthat is magnetized in the vertical direction with respect to a filmsurface and is provided on the front surface of the heavy metal layer 2,the barrier layer 11 that is provided on a surface of the recordinglayer 10 which is opposite to the heavy metal layer 2 and is formed froman insulator, and the reference layer 12 which is provided on a surfaceof the barrier layer 11 which is opposite to the recording layer 10 anda magnetization of the reference layer is fixed in the verticaldirection with respect to a film surface; the insulating layer 5 that isprovided on a surface of the heavy metal layer 2 which is opposite tothe magnetic recording unit 3; the first terminal T1 that is connectedto the insulating layer 5 at a position facing the recording layer 10with the heavy metal layer 2 and the insulating layer 5 interposedtherebetween and applies a voltage to the heavy metal layer 2 throughthe insulating layer 5; the second terminal T2 that is connected to thereference layer 12; and the third terminal T3 and the fourth terminal 14which are connected to the heavy metal layer 2, and cause the writecurrent to flow to the heavy metal layer 2 between the magneticrecording unit 3 and the insulating layer 5.

Accordingly, since the magnetoresistance effect element 1 includes theinsulating layer 5 of the heavy metal layer 2, and connection to theinsulating layer 5 is established at a position facing the recordinglayer 10 with the heavy metal layer 2 and the insulating layer 5interposed therebetween, the magnetization of the recording layer 10 canbe reversed by applying a voltage to the heavy metal layer 2 through theinsulating layer 5, and by causing the write current Iw to flow to theheavy metal layer 2, and the current does not flow to the magneticrecording unit 3 in writing. Accordingly, in the magnetoresistanceeffect element 1, it is possible to reduce the resistance of the MTJ ofthe magnetic recording unit 3 by reducing the thickness of the barrierlayer 11, and it is possible to speed up a read operation.

In addition, in the magnetoresistance effect element 1, in writing,since the write assist voltage V_(Assist) is applied to the heavy metallayer 2 through the insulating layer 5, even though a current is notcaused to flow to the magnetic recording unit 3, data can be written. Inreading, stored data can be read out only by causing the read current Irto flow to the magnetic recording unit 3. The voltage control line canbe changed between in writing and in reading, and it is possible torealize Read disturb free and Write disturb free.

Since spins performing the precession motion are injected to therecording layer 10, and the magnetization of the recording layer 10magnetized in the vertical direction is reversed due to the spinsperforming the precession motion, the magnetization of the recordinglayer 10 can be reversed without applying an external magnetic field.

(2) Magnetic Memory Array of Embodiment of Invention (2-1) OverallConfiguration of Magnetic Memory Array

As illustrated in FIG. 6, a magnetic memory array 30 of this embodimentincludes a heavy metal layer 2 having an elongated shape extending inthe first direction, a plurality of magnetic recording units 3, and aplurality of insulating layers 5. A configuration of the heavy metallayer 2, the magnetic recording units 3, and the insulating layers 5 arethe same as in the magnetoresistance effect element 1 except that thelength of the heavy metal layer 2 in the first direction is different,and thus description thereof will be omitted. In the magnetic memoryarray 30, the plurality of magnetic recording units 3 are arranged on afront surface of the heavy metal layer 2 having the elongated shape inthe first direction of the heavy metal layer 2. In the magnetic memoryarray 30, the number of the magnetic recording units 3 provided can beappropriately set, and in conformity to the number, the size of theheavy metal layer 2 or the magnetic recording units 3, or the like isdetermined. In FIG. 6, three magnetic recording units 3 a, 3 b, and 3 care illustrated as a representative. In addition, in FIG. 6, differentnumeral numbers are given to the magnetic recording units 3 a, 3 b, and3 c, respectively, but this is for convenience in distinguishment of therespective magnetic recording units 3 a, 3 b, and 3 c, andconfigurations thereof are the same as each other. That is, the magneticmemory array 30 includes a plurality of the magnetoresistance effectelements 1, the heavy metal layer 2 of one of the magnetoresistanceeffect elements 1 is extended in the first direction, the extended heavymetal layer 2 is shared by the other plurality of magnetoresistanceeffect elements 1, and the magnetic recording units 3 are arranged onthe front surface of the heavy metal layer 2 in the first direction.

The insulating layer 5 is provided on a rear surface of the heavy metallayer which is a surface opposite to the front surface of the heavymetal layer 2 on which the magnetic recording unit 3 is provided in thesame number as the number of the magnetic recording units 3, and arearranged on a lower portion of the magnetic recording units 3. In FIG.6, a different reference numeral is given for every insulating layerlike insulating layers 5 a, 5 b, and 5 c to distinguish the plurality ofinsulating layers. The insulating layers 5 a, 5 b, and 5 c arerespectively arranged at positions facing the recording layers 10 of themagnetic recording units 3 a, 3 b, and 3 c with the heavy metal layer 2interposed therebetween, and substantially cover bottom surfaces(surfaces of the magnetic recording units 3 a, 3 b, and 3 c which are incontact with the heavy metal layer 2) of the magnetic recording units 3a, 3 b, and 3 c.

As in the magnetoresistance effect element 1, terminals (a plurality offirst terminals T1, a plurality of second terminals T2, a third terminalT3, and a fourth terminal T4) are connected to the magnetic memory array30. Description of the same portion of the first terminals T1, thesecond terminals T2, the third terminal T3, and the fourth terminal T4as in the first terminal T1, the second terminal T2, the third terminalT3, and the fourth terminal T4 of the magnetoresistance effect element 1will be omitted.

The first terminals T1 are provided on a lower portion of the insulatinglayers 5 a, 5 b, and 5 c one by one. The first terminals T1 are providedon rear surfaces of the insulating layers 5 a, 5 b, and 5 c which areopposite to surfaces in contact with the heavy metal layer 2 to face theheavy metal layer 2 with the insulating layers 5 a, 5 b, and 5 cinterposed therebetween. The FET-type first transistor Tr1 is connectedto each of the first terminals T1. In the first transistor Tr1 connectedto the insulating layer 5 a, a source is connected to a first write bitline (not illustrated). In the first transistor Tr1 connected to theinsulating layer 5 b, a source is connected to a second write bit line(not illustrated). In the first transistor Tr1 connected to theinsulating layer 5 c, a source is connected to a third write bit line(not illustrated). A voltage level of each of the write bit lines is setto V_(Assist). When the first transistors Tr1 are turned on, a writeassist voltage V_(Assist) for reversing the magnetization M10 of therecording layer 10 of the magnetic recording unit 3 can be applied tothe heavy metal layer 2 through the insulating layer 5.

The second terminals T2 are provided on reference layers 12 of themagnetic recording units 3 a, 3 b, and 3 c in contact with referencelayers 12 (ferromagnetic layers 16 thereof). In addition, the FET-typesecond transistor Tr2 is connected to each of the second terminals T2.In the second transistor Tr2 connected to the magnetic recording unit 3a, a source is connected to a first read bit line (not illustrated). Inthe second transistor Tr2 connected to the magnetic recording unit 3 b,a source is connected to a second read bit line (not illustrated). Inthe second transistor Tr2 connected to the magnetic recording unit 3 c,a source is connected to a third read bit line (not illustrated). Avoltage level of each of the read bit lines is set to V_(Read), and whenthe second transistors Tr2 are turned on, the read voltage V_(Read) isapplied to the second terminals T2.

The third terminal T3 and the fourth terminal T4 are provided on one endand on the other end of the heavy metal layer 2, and the plurality ofmagnetic recording units 3 are arranged between the both terminals. Inthis embodiment, the third terminal T3 is provided on a front surface ofone end of the heavy metal layer 2 in the first direction, and thefourth terminal T4 is provided on a front surface of the other end ofthe heavy metal layer 2 in the first direction. The third terminal T3 isconnected to the FET-type third transistor Tr3, and the fourth terminalT4 is connected to the ground. In the third transistor Tr3, a source isconnected to a control line (not illustrated). A voltage level of thecontrol line is set to V_(W), and when the third transistor Tr3 isturned on, the write voltage V_(W) is applied to the third terminal T3,and the write current Iw flows between the third terminal T3 and thefourth terminal T4 in the first direction.

When turning on the second transistor Tr2 connected to the magneticrecording unit 3 a through the second terminal T2 and the thirdtransistor Tr3, the read current Ir for reading a resistance value ofthe magnetic recording unit 3 a flows through the magnetic recordingunit 3 a. In this embodiment, since V_(W) is set to be higher thanV_(Read), the read current Ir can be caused to flow from the thirdterminal T3 to the second terminal T2 through the heavy metal layer 2and the magnetic recording unit 3 a. This is true of the magneticrecording unit 3 b and 3 c.

As described above, in this embodiment, the third terminal T3 and thefourth terminal T4 are provided on the front surface of the heavy metallayer 2, and contact from an upper side to the magnetic memory array 30is made, but there is no limitation thereto. For example, the thirdterminal T3 and the fourth terminal T4 may be provided on the rearsurface of the heavy metal layer 2, and contact from a lower side to themagnetic memory array 30 may be made.

(2-2) Write Method and Read Method for Magnetic Memory Array

Description will be given of a write method for the magnetic memoryarray 30 with reference to FIG. 7A and FIG. 7B in which the samereference numeral is given to the same configuration as in FIG. 6.Similarly, in the magnetic memory array 30, resistance of each of themagnetic recording units 3 a, 3 b, and 3 c varies depending on whetherthe magnetization directions of the recording layer 10 and the referencelayer 12 are parallel or anti-parallel. In the magnetic memory array 30,as in the magnetoresistance effect element 1, one-bit data of “0” andone-bit data of “1” are allocated to the parallel state and theanti-parallel state, respectively, by using a situation in which aresistance value of each of the magnetic recording units 3 a, 3 b, and 3c is different between the parallel state and the anti-parallel state,thereby storing data in the magnetoresistance effect element 1.

The write method for the magnetic memory array 30 will be described inmore detail with reference to a case where the spin hall angle of theheavy metal layer 2 is positive. A relationship of a magnetizationdirection of the recording layer 10 of the magnetic recording unit 3 a,3 b, or 3 c, and a sign of the write assist voltage V_(Assist) forreversing the magnetization of the recording layer 10 and a direction inwhich the write current Iw is caused to flow is the same as in themagnetoresistance effect element 1. In the magnetic memory array 30, itis assumed that in an initial state, the magnetic recording units 3 aand 3 b are storing data “0” in the parallel state with themagnetization direction of the recording layer 10 facing downward, andthe magnetic recording unit 3 c stores data “1” in the anti-parallelstate with the magnetization direction of the recording layer 10 facingupward. In addition, it is assumed that all of the first transistorsTr1, the second transistors Tr2, and the third transistors Tr3 areturned off. In addition, in this example, it is assumed that data iswritten to the magnetic recording units 3 a and 3 c, and data is notwritten to the magnetic recording unit 3 b.

First, in the magnetic memory array 30, as illustrated in FIG. 7A, thefirst transistors Tr1 which are respectively connected to the insulatinglayers 5 a and 5 c are turned on, a negative write assist voltageV_(Assist) is applied from the first terminal T1 to the heavy metallayer 2 through the insulating layer 5 a, and a positive write assistvoltage V_(Assist) is applied from the first terminal T1 to the heavymetal layer 2 through the insulating layer 5 c. As a result, an electricfield in the +z-direction occurs in the heavy metal layer 2 on a lowerside of the magnetic recording unit 3 a, and an electric field in the−z-direction occurs in the heavy metal layer 2 on a lower side of themagnetic recording unit 3 b.

Next, as illustrated in FIG. 7B (in FIG. 7B, a magnetization directionof the recording layer 10 after writing is illustrated), the firsttransistor Tr1 is retained to the ON state, the third transistor Tr3 isturned on, the write voltage V_(W) is applied to the third terminal T3,and the write current Iw is caused to flow between the one end and theother end of the heavy metal layer 2. At this time, since the writevoltage V_(W) is set to be higher than the ground voltage, the writecurrent Iw flows from the third terminal T3 to the fourth terminal 14through the heavy metal layer 2, and the write current Iw flows from theone end of the heavy metal layer 2 to the other end in the +x-direction.

When the write current Iw flows to the heavy metal layer 2, a spincurrent (spin angular motion current) occurs in the heavy metal layer 2due to a spin hall effect by a spin orbit interaction, and spinsdirected to a paper-surface front side (−y-direction in FIG. 1A) flow tothe upper surface side (+z-direction) of the heavy metal layer 2, spinswhich are anti-parallel to the spins in a direction and are directed toa paper surface depth side (+y-direction in FIG. 1A) flow to the lowersurface side (−z-direction) of the heavy metal layer 2, and the spinsare unevenly distributed in the heavy metal layer 2.

At this time, since an electric field in the z-direction occurs in theheavy metal layer 2 on the lower side of the magnetic recording units 3a and 3 c, spins which are unevenly distributed perform precessionalmotion due to a Rashba effect, and the spins having performed theprecessional motion flow into the recording layer 10 of the magneticrecording units 3 a and 3 c due to the spin current flowing through theheavy metal layer 2. At this time, since the write current Iw flowsthrough the magnetic recording unit 3 a in the +x-direction, and thenegative assist voltage V_(Assist) is applied to the heavy metal layer 2on the lower side of the magnetic recording unit 3 a, a downwardmagnetization M10 is reversed to upward due to the spins which haveperformed the precessional motion and flowed into the recording layer10. As a result, the magnetic recording unit 3 a enters theanti-parallel state, and data “1” is stored. In addition, since thewrite current Iw flows through the magnetic recording unit 3 c in the+x-direction, and a positive assist voltage V_(Assist) is applied to theheavy metal layer 2 on the lower side of the magnetic recording unit 3c, an upward magnetization M10 is reversed to downward due to the spinswhich have performed the precessional motion and flowed into therecording layer 10. As a result, the magnetic recording unit 3 c entersthe parallel state, and data “0” is stored.

On the other hand, since the assist voltage is not applied to themagnetic recording unit 3 b, even when spins which are unevenlydistributed due to flowing of the write current Iw in the +x-directionflow into the recording layer 10 due to the spin current, magnetizationreversal does not occur. As a result, the magnetic recording unit 3 b isretained to the parallel state, and stores data “0”. As described above,the first transistor Tr1 has a function as a bit selection transistorthat selects a write bit (the magnetic recording units 3 a and 3 c).

After data writing, each of the first transistors Tr1 is turned offafter the third transistor Tr3 is turned off. That is, application ofthe write voltage V_(W) is stopped after the write current Iw is set toOFF.

As described above, in the magnetic memory array 30, the magnetizationdirection of the recording layer 10 of the magnetic recording units 3 aand 3 c which are selected is reversed by causing the write current Iwto flow to the heavy metal layer 2 while applying a voltage to the heavymetal layer 2 through the insulating layers 5 a and 5 c which areselected, and thus data “0” or “1” data can be collectively written, andthe magnetic recording unit 3 b that is not selected can retain data. Inaddition, in the write operation, each of the second transistors Tr2 isalways turned off, and thus a current does not flow to the magneticrecording unit 3 in data writing differently from the magnetoresistanceeffect element in the related art. According to this, in the magneticmemory array 30, a resistance value of the magnetic recording unit 3 canbe made small by reducing the thickness of the barrier layer 11 of eachof the magnetic recording units 3 a, 3 b, and 3 c, time necessary forthe write operation can be shortened, and high speed of themagnetoresistance effect element 1 can be realized.

Next, description will be given of a data read method for the magneticmemory array 30 with reference to FIG. 8. It is assumed that in aninitial state, all transistors are turned off, and data stored in themagnetic recording unit 3 b is read. The third transistor Tr3 is turnedon to apply the write voltage V_(W) to the third terminal T3, and thesecond transistor Tr2 connected to the magnetic recording unit 3 b isturned on to apply the read voltage V_(Read) to the second terminal T2connected to the magnetic recording unit 3 b. At this time, since theread voltage V_(Read) is set to be lower than the write voltage V_(W),the read current Ir flows from the third terminal T3 to the heavy metallayer 2, the magnetic recording unit 3 b, and the second terminal T2 inthis order. The magnitude of the read current Ir varies depending on theresistance value of the magnetic recording unit 3 b, and thus asituation as to whether the magnetic recording unit 3 b is in theparallel state or the anti-parallel state, that is, whether the magneticrecording unit 3 is storing data “0” or data “1” can be read out fromthe magnitude of the read current Ir.

Then, after the second transistor Tr2 is turned off, the thirdtransistor Tr3 is turned off. Since the third transistor Tr3 is turnedoff after the second transistor Tr2, that is, since the write voltageV_(W) is set to OFF after the read voltage V_(Read), it is possible tosuppress a current from flowing from the second terminal to the thirdterminal through the magnetic recording unit 3 b and the heavy metallayer 2, and thus the barrier layer 11 can be protected, and the barrierlayer 11 can be made thinner. In addition to this, it is also possibleto suppress Read disturb in which the magnetization state of therecording layer 10 varies due to a current flowing through the magneticrecording unit 3 b.

In this manner, in the magnetic memory array 30, since the write assistvoltage V_(Assist) is applied to the first terminal T1 in writing, theread voltage V_(Read) is applied to the second terminal T2 in reading,and a voltage control line in writing and a voltage control line inreading are different from each other, it is possible to realize Readdisturb free and Write disturb free.

(2-3) Modification Example of Magnetic Memory Array of Embodiment ofInvention

In the embodiment, description has been given of a case where themagnetic memory array 30 includes a plurality of insulating layers 5 a,5 b, and 5 c which are respectively arranged on a lower side of themagnetic recording units 3 a, 3 b, and 3 c, but the invention is notlimited to this case. For example, as in an insulating layer 51 of amagnetic memory array 31 illustrated in FIG. 9A, a cross-sectional shapeof the insulating layer 51 in an in-plane direction may be set to thesame shape as in the heavy metal layer 2, and the insulating layer 51may cover the entirety of a rear surface of the heavy metal layer 2. Inthis case, the insulating layer 51 and the heavy metal layer 2 can becontinuously stacked, and a process of shaping the insulating layer to,for example, a circular column shape or the like can be omitted, andthus the magnetic memory array can be manufactured in an easier manner.

The shape of the insulating layers 5 a, 5 b, and 5 c is not particularlylimited as long as the insulating layers 5 a, 5 b, and 5 c cansubstantially cover bottom surfaces of the magnetic recording units 3 a,3 b, and 3 c from the rear surface side of the heavy metal layer 2, andmay be various shapes such as a triangular shape, a quadrangular shape,a polygonal shape of a quadrangle or greater, and an elliptical shape.

As in a magnetic memory array 32 illustrated in FIG. 9B, a diode 17 maybe provided on the ferromagnetic layer 16 of the reference layer 12. Inthe diode 17, an anode side is in contact with the ferromagnetic layer16, and a cathode side is in contact with the second terminal T2, andthus a current is suppressed from flowing from the second terminal T2 tothe heavy metal layer 2. In this case, in the read operation, since theread voltage V_(Read) is higher than the ground voltage, a current issuppressed from flowing from the second terminal T2 to the fourthterminal T4 through the magnetic recording unit and the heavy metallayer 2, and thus the thickness of the barrier layer 11 can be madesmaller. In addition, a cross point type magnetic memory device to bedescribed later is realized.

In the embodiment, description has been given of a case where theinsulating layers 5 a, 5 b, and 5 c and the first terminal T1, and themagnetic recording units 3 a, 3 b, and 3 c have the same shape in across-sectional shape in an in-plane direction, and the magneticrecording units 3 a, 3 b, and 3 c, and the insulating layers 5 a, 5 b,and 5 c are arranged to overlap each other, respectively (a case wherethe magnetic recording units 3 a, 3 b, and 3 c, and the insulatinglayers 5 a, 5 b, and 5 c and the first terminal T1 have a flushstructure in self-alignment), but the invention is not limited to thiscase. As described above in FIG. 5D, in the magnetoresistance effectelement, it is preferable that a cross-sectional area of each of theinsulating layers 5 a, 5 b, and 5 c, and the first terminal T1 in thein-plane direction is set to be greater than a cross-sectional area ofeach of the magnetic recording units 3 a, 3 b, and 3 c in the in-planedirection, and a voltage is applied to the entirety of lower portions ofthe magnetic recording units 3 a, 3 b, and 3 c, but the cross-sectionalarea of each of the insulating layers 5 a, 5 b, and 5 c, and the firstterminal T1 in the in-plane direction may be set to be smaller than thecross-sectional area of each of the magnetic recording units 3 a, 3 b,and 3 c in the in-plane direction.

In a case where the insulating layers 5 a, 5 b, and 5 c, and the firstterminal T1, and the magnetic recording units 3 a, 3 b, and 3 c areformed in the same shape and size in the cross-section, for example, asin a magnetic memory array 30 a illustrated in FIG. 9C, positions of themagnetic recording units 3 a, 3 b, and 3 c, and the insulating layers 5a, 5 b, and 5 c may deviate from each other, and the magnetic recordingunits 3 a, 3 b, and 3 c, and the insulating layers 5 a, 5 b, and 5 c andthe first terminal T1 may not have the flush structure in theself-alignment.

Description has been given of the magnetic memory array 31 in which thecross-sectional shape of the insulating layer 51 in the in-planedirection is the same as in the heavy metal layer 2, the insulatinglayer 51 completely covers the rear surface of the heavy metal layer 2,and the magnetic recording units 3 a, 3 b, and 3 c, and the firstterminal T1 are arranged to overlap each other. However, the inventionis not limited thereto, and the cross-sectional area of the firstterminal T1 in the in-plane direction may be set to be greater orsmaller than the cross-sectional area of each of the magnetic recordingunits 3 a, 3 b, and 3 c in the in-plane direction, and as in a magneticmemory array 31 a illustrated in FIG. 9D, the magnetic recording units 3a, 3 b, and 3 c, and the first terminal T1 may not have the flushstructure in the self-alignment. In addition, with respect to a magneticmemory array 32 a including a diode 17 on the ferromagnetic layer 16 ofthe reference layer 12 as illustrated in FIG. 9E, similarly, themagnetic recording units 3 a, 3 b, and 3 c, and the insulating layers 5a, 5 b, and 5 c and the first terminal T1 may not have the flushstructure in the self-alignment. Note that, even in this case, thecross-sectional area of each of the insulating layers 5 a, 5 b, and 5 c,and the first terminal T1 in the in-plane direction may be set to begreater or smaller than the cross-sectional area of each of the magneticrecording units 3 a, 3 b, and 3 c in the in-plane direction.

In the magnetic memory array 30, a conductive layer formed from a metalwith high conductivity may be inserted into the heavy metal layer 2between adjacent magnetic recording units 3. For example, as in amagnetic memory array 33 illustrated in FIG. 10A, a conductive layer 26a is disposed in the heavy metal layer 2 between the magnetic recordingunit 3 a and the magnetic recording unit 3 b, a conductive layer 26 b isprovided in the heavy metal layer 2 in adjacent to the magneticrecording unit 3 b, a conductive layer 26 c is provided in the heavymetal layer 2 in adjacent to the magnetic recording unit 3 c, and aconductive layer 26 d is provided in the heavy metal layer 2 between themagnetic recording unit 3 c and the magnetic recording unit 3 d. In thismanner, the magnetic memory array 33 has a configuration in which aplurality of the magnetoresistance effect elements 1 are connected inseries through the conductive layers 26. In this case, in the magneticmemory array 33, the resistance of the heavy metal layer 2 can bereduced, and thus an adverse effect of voltage drop in the heavy metallayer 2 can be suppressed, and energy consumption can be furtherreduced. Note that, as in a magnetic memory array 34 illustrated in FIG.10B, even in a case where conductive layers 26 a, 26 b, 26 c, and 26 dare arranged on the heavy metal layer 2 between the magnetic recordingunits 3 a, 3 b, 3 c, and 3 d adjacent to each other, the same effect canbe obtained. It is preferable that the conductive layer 26 is formedfrom, for example, Ta, W, Cu, Al, Ti, or an alloy containing at leastone or more of these elements.

In the magnetic memory array 30, two magnetic recording units adjacentto each other may be set as a pair, a terminal may be provided on aheavy metal layer between the two magnetic recording units, and datastored in a bit may be read out by using the terminal. For example, in amagnetic memory array 35 illustrated in FIG. 10C, a first terminal T5 isprovided between the magnetic recording units 3 a and 3 b adjacent toeach other, and the magnetic recording units 3 c and 3 d adjacent toeach other. In addition, each bit performs storage so that in a state inwhich one magnetic recording unit is in an anti-parallel state, and theother magnetic recording unit is in a parallel state.

In the magnetic memory array 35, for example, the read current Ir iscaused to flow from the reference layer 12 of the magnetic recordingunit 3 b to the reference layer 12 of the magnetic recording unit 3 athrough the heavy metal layer 2, an intermediate potential between themagnetic recording unit 3 b and the magnetic recording unit 3 a ismeasured with the fifth terminal T5, and stored data can be read out onthe basis of the measured intermediate potential. The read current Ircan flow from the reference layer 12 of the magnetic recording unit 3 bto the reference layer 12 of the magnetic recording unit 3 a through theheavy metal layer 2 by setting the read voltage V_(Read) applied to themagnetic recording unit 3 a to be smaller than the read voltage V_(Read)applied to the magnetic recording unit 3 b, and by turning on only thesecond transistor Tr2 connected to the magnetic recording units 3 a and3 b.

Stored data can also be read out by applying a predetermined voltage tothe second terminal T2 of the magnetic recording unit 3 b, by settingthe second terminal of the magnetic recording unit 3 a to the groundlevel, by applying the read voltage V_(Read) to the fifth terminal T5,and by detecting the read current Ir that flows into the fifth terminalT5. In addition, the second terminal T2 of the magnetic recording unit 3a and the second terminal of the magnetic recording unit 3 b may beconnected to a differential amplifier, and stored data can also be readout on the basis of a voltage that is output in correspondence with adifference in a resistance value between the magnetic recording units 3a and 3 b.

As described above, when the two magnetic recording units are set toread out data stored as a pair, data can be read out at a higher speedin comparison to a case where stored data is sequentially read out forevery magnetic recording unit. In a case where the magnetic memory arrayincludes a larger number of magnetic recording units, data read time canbe further shortened.

(2-4) Operation and Effect

In the above-described configuration, the magnetic memory array 30includes a plurality of the magnetoresistance effect elements 1, theheavy metal layer 2 of one of the magnetoresistance effect elements 1extends in the first direction, the extended heavy metal layer 2 isshared by the other plurality of magnetoresistance effect elements 1,and the magnetic recording units 3 a, 3 b, and 3 c are arranged in thefirst direction on the heavy metal layer 2.

Accordingly, since the magnetic memory array 30 includes the pluralityof magnetoresistance effect elements 1, the magnetization of therecording layer 10 of the magnetic recording units 3 a, 3 b, and 3 c canbe reversed by applying a voltage to the heavy metal layer 2 through theinsulating layers 5 a, 5 b, and 5 c, and by causing the write current Iwto flow to the heavy metal layer 2, and a current does not flow to themagnetic recording units 3 a, 3 b, and 3 c in writing. According tothis, in the magnetic memory array 30, it is possible to reduce theresistance of the MTJ of the magnetic recording units 3 a, 3 b, and 3 cby reducing the thickness of the barrier layer 11, and it is possible tospeed up a read operation.

In addition, in the magnetoresistance effect element 1, in writing,since the write assist voltage V_(Assist) is applied to the heavy metallayer 2 through the insulating layers 5 a, 5 b, and 5 c, even though acurrent is not caused to flow to the magnetic recording units 3 a, 3 b,and 3 c, data can be written. In reading, stored data can be read outonly by causing the read current Ir to flow to the magnetic recordingunits 3 a, 3 b, and 3 c. The voltage control line can be changed betweenin writing and in reading, and it is possible to realize Read disturbfree and Write disturb free.

(3) Magnetic Memory Device Using Magnetic Memory Array of thisEmbodiment

A magnetic memory device can be configured by a plurality of themagnetic memory arrays 30 of this embodiment in a direction(y-direction) orthogonal to the first direction. An example of themagnetic memory device will be described with reference to FIG. 11 inwhich the same reference numeral is given to the same configuration asin FIG. 6. For convenience of explanation, arrangement of the magneticrecording units on the heavy metal layer 2 (x-direction) is referred toas a row, and arrangement of the magnetic recording units in a direction(y-direction) orthogonal to the heavy metal layer 2 is referred to as acolumn.

In a magnetic memory device 50, a plurality of magnetic memory arrays 30a, 30 b, 30 c, 30 d, and 30 e are arranged in the y-direction, and themagnetic recording units 3 a, 3 b, and 3 c of the magnetic memory arrays30 a, 30 b, 30 c, 30 d, and 30 e are arranged in the y-direction,respectively. In this embodiment, a plurality of the magnetic recordingunits 3 a, a plurality of the magnetic recording units 3 b, and aplurality of the magnetic recording units 3 c are arranged in the samecolumn, respectively. In this embodiment, five pieces of the magneticmemory arrays 30 a, 30 b, 30 c, 30 d, and 30 e are arranged, but thenumber of the magnetic memory arrays arranged is not limited. Inaddition, when the magnetic recording units are arranged in they-direction, it is not necessary for the magnetic recording units 3 a tobe arranged in the same column, and the magnetic recording unit 3 a andthe magnetic recording unit 3 b may be arranged in the same column.

In the magnetic memory device 50, first elongated terminals T1 a, T1 b,and T1 c are formed in a film shape extending in a direction(y-direction) orthogonal to the first direction. In the magnetic memorydevice 50, the first elongated terminals T1 a, T1 b, and T1 c areprovided one by one at positions facing the plurality of arrangedmagnetic recording units 3 a (3 b or 3 c) with the heavy metal layer 2 aand the insulating layer 5 a (5 b or 5 c) interposed therebetween forevery column of the magnetic recording units 3 a, 3 b, and 3 c, and arerespectively shared by the magnetic recording units 3 a, 3 b, or 3 cwhich are arranged in the same column. Drains of first transistors Tr1a, Tr1 b, and Tr1 c are respectively connected to the first elongatedterminals T1 a, T1 b, and T1 c, which are provided, at one end in theextending direction, and the first transistors Tr1 which arerespectively connected to the first terminals T1 are grouped into onefor every column.

As described above, in the magnetic memory device 50, since the firstelongated terminal T1 a, T1 b, or T1 c to be shared is provided forevery column, it is possible to reduce the number of the firsttransistors to one for every column, and space saving is realized, andthus a high-density memory can be realized.

Sources and gates of the first transistors Tr1 a, Tr1 b, and Tr1 c areconnected to a control device (not illustrated), and when the controldevice applies a voltage to the gate to turn on the first transistorsTr1 a, Tr1 b, and Tr1 c, the write assist voltage V_(Assist) is appliedfrom the control device to the first elongated terminals T1 a, T1 b, andT1 c. Accordingly, for example, when the first transistor Tr1 a isturned on, the write assist voltage V_(Assist) is applied to the heavymetal layer 2 on a lower side of the magnetic recording unit 3 a of themagnetic memory arrays 30 a, 30 b, 30 c, 30 d, and 30 e through theinsulating layer 5.

The second transistors Tr2 connected to the magnetic recording units 3a, 3 b, or 3 c are connected to the same read word line for every columnof the magnetic recording units. In this embodiment, the secondtransistors Tr2 respectively connected to the magnetic recording units 3a of the magnetic memory arrays 30 a, 30 b, 30 c, 30 d, and 30 e areconnected to a first read word line 41 a, the second transistors Tr2respectively connected to the magnetic recording units 3 b are connectedto a second read word line 41 b, and the second transistors Tr2respectively connected to the magnetic recording units 3 c are connectedto a third read word line 41 c. The first read word line 41 a, thesecond read word line 41 b, and the third read word line 41 c areconnected to a control unit (not illustrated), and a voltage level isset to the read voltage V_(Read).

Next, a write method for the magnetic memory device 50 will bedescribed. A relationship of a magnetization direction of the recordinglayer of the magnetic recording units 3 a, 3 b, and 3 c, and a directionof the write current Iw for reversing the magnetization direction of therecording layer, and a sign of the write assist voltage V_(Assist) isthe same as in the magnetic memory array 30, and thus descriptionthereof will be omitted here. Here, description will be given withreference to a case where data is written to the magnetic recording unit3 b of the magnetic memory array 30 a. It is assumed that alltransistors are turned off after a write operation and a read operation,and all transistors are turned off before the write operation and theread operation.

First, the first transistor Tr1 b connected to the first elongatedterminal T1 b in a column where the magnetic recording unit 3 b to bewritten exists is turned on, and the write assist voltage V_(Assist) isapplied to the heavy metal layer 2 on the lower side of the magneticrecording unit 3 b through the insulating layer 5. Next, the thirdtransistor Tr3 connected to the magnetic memory array 30 a in a columnwhere the magnetic recording unit 3 b to be written exists is turned onto cause the write current Iw to flow from one end to the other end ofthe heavy metal layer 2 of the magnetic memory array 30 a. According tothis, a magnetization of the recording layer of the magnetic recordingunit 3 b to be written is reversed, and data is written. In this manner,in the magnetic memory device 50, data is written to a magneticrecording unit (magnetic recording unit 3 b) existing at an intersectionof a selected column (the first elongated terminal T1 b) and a selectedrow (the magnetic memory array 30 a).

In the magnetic memory device 50, data may be collectively written to aplurality of magnetic recording units by selecting a plurality of rowsand a plurality of columns. In addition, data “0” or data “1” can becollectively written to a plurality of magnetic recording units bymaking the sign of the write assist voltage V_(Assist) different forevery column or by making a flowing direction of the write current Iwdifferent for every row.

Next, a read method for the magnetic memory device 50 will be described.Here, description will be given of a case where data of the magneticrecording unit 3 b of the magnetic memory array 30 a is read out as anexample. First, the third transistor Tr3 connected to the magneticmemory array 30 a in a column where the magnetic recording unit 3 b tobe read exists is turned on. Next, the second transistor Tr2 connectedto the magnetic recording unit 3 of the magnetic memory array 30 a isturned on, and the read current Ir is caused to flow from the thirdterminal T3 to the second terminal through the heavy metal layer 2. Inaddition, data written to the magnetic recording unit 3 b is read outfrom the read current Ir. In this manner, in the magnetic memory device50, data is read out by selecting the magnetic recording unit (themagnetic recording unit 3 b) to be read out by turning on the thirdtransistor Tr3 in the magnetic memory array where the magnetic recordingunit exists and by turning on the second transistor Tr2 connected to themagnetic recording unit.

When a plurality of the magnetic memory arrays 32 including the magneticrecording units 22 a, 22 b, and 22 c provided with a diode 17 on thereference layer are arranged in a direction (y-direction) orthogonal tothe first direction, as in a magnetic memory device 52 illustrated inFIG. 12 in which the same reference numeral is given to the sameconfiguration as in FIG. 9B, the magnetic memory device capable ofsaving a space by grouping the second transistors Tr2 to one for everycolumn is realized. Description will be given of the magnetic memorydevice 52 with focus given to a configuration different from themagnetic memory device 50. The magnetic memory device 52 is the same asthe magnetic memory device 50 in an arrangement method of the magneticmemory arrays 32 and in a configuration of the first elongated terminalsT1 a, T1 b, and T1 c, and thus description thereof will be omitted.

In the magnetic memory device 52, second elongated terminals T2 a, T2 b,and T2 c are formed in a film shape extending in the y-direction, andare provided at positions facing a plurality of arranged magneticrecording units 22 a, 22 b, or 22 c one by one for every column of themagnetic recording units 22 a, 22 b, or 22 c. The second elongatedterminal T2 a, T2 b, or T2 c is in contact with diodes 17 of theplurality of magnetic recording units 22 a, 22 b, or 22 c which arearranged, and is shared by the magnetic recording units 22 a, 22 b, or22 c which are arranged in the same column. Drains of second transistorsTr2 a, Tr2 b, and Tr2 c are respectively connected to the secondelongated terminals T2 a, T2 b, and T2 c at one end in the extendingdirection (y-direction), and the second transistors Tr2 which arerespectively connected to the second terminals T2 are grouped into onefor every column. Sources of the second transistors Tr2 a, Tr2 b, andTr2 c are connected to a control device (not illustrated), and a voltagelevel is set to the read voltage V_(Read). Gates of the secondtransistors Tr2 a, Tr2 b, and Tr2 c are connected to the control device,and are turned on or off by the control device.

In the magnetic memory device 52, each of the magnetic recording units22 a, 22 b, and 22 c includes the diode 17, and a current is suppressedfrom flowing from the second elongated terminals T2 a, T2 b, and T2 c tothe heavy metal layer 2. According to this, in the magnetic memorydevice 52, even when applying the read voltage V_(Read) to the secondelongated terminals T2 a, T2 b, and T2 c in data reading, a current doesnot flow from the second elongated terminals T2 a, T2 b, and T2 c tomagnetic recording units (the magnetic recording units 22 a and 22 c)other than a magnetic recording unit (for example, the magneticrecording unit 22 b) from which data is read out. Accordingly, it is notnecessary to connect the second transistor Tr2 to the magnetic recordingunits 22 a, 22 b, and 22 c, and it is not necessary to turn off atransistor of a magnetic recording unit to which a current is notdesired to flow. Accordingly, the second transistor Tr2 may not beconnected to the magnetic recording units 22 a, 22 b, and 22 c.Accordingly, when the second transistors Tr2 a, Tr2 b, or Tr2 c isprovided in the second elongated terminal T2 a, T2 b, or T2 c one byone, the number of transistors is reduced, and thus space saving can berealized.

A write method for the magnetic memory device 52 is the same as in themagnetic memory device 50, and thus description thereof will be omitted.Next, a read method for the magnetic memory device 52 will be described.Here, description will be given of a case where data of the magneticrecording unit 22 b of the magnetic memory array 32 a is read out as anexample. First, the third transistor Tr3 connected to the magneticmemory array 32 a in a column where the magnetic recording unit 22 b tobe read exists is turned on. Next, the second transistor Tr2 b of thesecond elongated terminal T2 b connected to the magnetic recording unit22 b of the magnetic memory array 32 a is turned on, the read voltageV_(Read) is applied to the second elongated terminal T2 b, and the readcurrent Ir is caused to flow from the third terminal T3 to the secondterminal T2 through the heavy metal layer 2. In addition, data writtento the magnetic recording unit 22 b is read out from the read currentIr. In this manner, in the magnetic memory device 52, stored data isread out from a magnetic recording unit (the magnetic recording unit 22b) existing at an intersection of a selected column (the secondelongated terminal T2 b) and a selected row (the magnetic memory array32 a).

Accordingly, in the magnetic memory device 52, data is written to amagnetic recording unit (magnetic recording unit 22 a) existing at anintersection of a selected column (for example, the first elongatedterminal T1 a) and a selected row (for example, the magnetic memoryarray 32 a), and data is read out from a magnetic recording unit (themagnetic recording unit 22 b) existing at an intersection of a selectedcolumn (for example, the second elongated terminal T2 b) and a selectedrow (for example, the magnetic memory array 32 a). A so-called crosspoint type memory device is realized.

In the magnetic memory device 52, since the magnetic recording units 22a, 22 b, or 22 c arranged in a direction orthogonal to the firstdirection share the first elongated terminal T1 a, T1 b, or T1 c, andshare the second elongated terminal T2 a, T2 b, or T2 c, the number ofthe first transistors and the number of the second transistors can bereduced to one for every first elongated terminal T1 a, T1 b, or T1 c,and for every second elongated terminal T2 a, T2 b, or T2 c.Accordingly, a space can be further saved, and a magnetic memory devicewith a higher density can be configured.

Data can also be collectively written to a plurality of magneticrecording units by selecting a plurality of rows and a plurality ofcolumns in the magnetic memory device 50 as in the magnetic memorydevice 52. In addition, data “0” or data “1” can be collectively writtento a plurality of magnetic recording units by making the sign of thewrite assist voltage V_(Assist) different for every column or by makinga flowing direction of the write current Iw different for every row.

REFERENCE SIGNS LIST

-   -   1, 1 a, 1 b Magnetoresistance effect element    -   2 Heavy metal layer    -   10 Recording layer    -   11 Barrier layer    -   12 Reference layer    -   30, 31, 32, 33 Magnetic memory array    -   50, 52 Magnetic memory device    -   Iw Write current    -   Ir Read current

The invention claimed is:
 1. A magnetoresistance effect elementcomprising: a heavy metal layer; a magnetic recording unit including arecording layer that includes a ferromagnetic layer that is magnetizedin a vertical direction with respect to a film surface and is providedon a front surface of the heavy metal layer, a barrier layer that isprovided on a surface of the recording layer which is opposite to theheavy metal layer and is formed from an insulator, and a reference layerwhich is provided on a surface of the barrier layer which is opposite tothe recording layer, and a magnetization of the reference layer is fixedin the vertical direction with respect to a film surface; an insulatinglayer that is provided on a surface of the heavy metal layer which isopposite to the magnetic recording unit; a first terminal that isconnected to the insulating layer at a position facing the recordinglayer with the heavy metal layer and the insulating layer interposedtherebetween and applies a voltage to the heavy metal layer through theinsulating layer; a second terminal that is connected to the referencelayer; and a third terminal and a fourth terminal which are connected tothe heavy metal layer, and cause a write current to flow to the heavymetal layer between the magnetic recording unit and the insulatinglayer.
 2. The magnetoresistance effect element according to claim 1,wherein when a voltage is applied from the first terminal to the heavymetal layer through the insulating layer, and the write current flowsbetween the third terminal and the fourth terminal, a magnetization ofthe recording layer is reversed.
 3. The magnetoresistance effect elementaccording to claim 1, wherein the insulating layer is provided at aposition facing the magnetic recording unit with the heavy metal layerinterposed therebetween.
 4. The magnetoresistance effect elementaccording to claim 1, wherein the insulating layer is provided on theentirety of the surface of the heavy metal layer on a side opposite tothe front surface.
 5. The magnetoresistance effect element according toclaim 1, wherein the insulating layer is formed from an insulator with ahigh dielectric constant.
 6. The magnetoresistance effect elementaccording to claim 1, wherein when the magnetization of the recordinglayer of the magnetic recording unit is reversed, a voltage applied tothe second terminal is set to OFF, and when a read current flows betweenthe heavy metal layer and the second terminal, a voltage applied to thefirst terminal is set to OFF.
 7. The magnetoresistance effect elementaccording to claim 1, wherein a diode is provided between the referencelayer and the second terminal.
 8. The magnetoresistance effect elementaccording to claim 7, wherein the diode suppresses a current fromflowing from the second terminal to the heavy metal layer.
 9. A magneticmemory array comprising: a plurality of the magnetoresistance effectelements according to claim 1, wherein the heavy metal layer of one ofthe magnetoresistance effect elements extends in a first direction, theextended heavy metal layer is shared by the other plurality ofmagnetoresistance effect elements, and the magnetic recording units arearranged in the first direction on the front surface of the heavy metallayer.
 10. The magnetic memory array according to claim 9, wherein aplurality of the magnetic recording units are arranged between the thirdterminal and the fourth terminal.
 11. A magnetic memory devicecomprising: a plurality of the magnetic memory arrays according to claim9 which is arranged in a direction orthogonal to the first direction.12. The magnetic memory device according to claim 11, furthercomprising: a plurality of first elongated terminals extending in adirection orthogonal to the first direction, wherein the plurality ofmagnetic recording units are arranged in a direction orthogonal to thefirst direction, and the first elongated terminals are provided atpositions facing the plurality of arranged magnetic recording units withthe heavy metal layer and the insulating layer interposed therebetween.13. A magnetic memory device comprising: a magnetic memory arrayincluding a plurality of the magnetoresistance effect elements accordingto claim 7, the heavy metal layer of one of the magnetoresistance effectelements extending in a first direction, the extended heavy metal layerbeing shared by the other plurality of magnetoresistance effectelements, the magnetic recording units being arranged in the firstdirection on the front surface of the heavy metal layer; a plurality offirst elongated terminals extending in a direction orthogonal to thefirst direction; and a plurality of second elongated terminals extendingin a direction orthogonal to the first direction, wherein a plurality ofthe magnetic memory arrays are arranged in a direction orthogonal to thefirst direction, a plurality of the magnetic recording units arearranged in a direction orthogonal to the first direction, the firstelongated terminals are provided at positions facing the plurality ofarranged magnetic recording units with the heavy metal layer and theinsulating layer interposed therebetween, and the second elongatedterminals are provided at positions facing the plurality of arrangedmagnetic recording units, and are in contact with the diode.
 14. A writemethod for a magnetoresistance effect element including a heavy metallayer, a magnetic recording unit including a recording layer thatincludes a ferromagnetic layer that is magnetized in a verticaldirection with respect to a film surface and is provided on a frontsurface of the heavy metal layer, a barrier layer that is provided on asurface of the recording layer which is opposite to the heavy metallayer and is formed from an insulator, and a reference layer which isprovided on a surface of the barrier layer which is opposite to therecording layer, and a magnetization of the reference layer is fixed inthe vertical direction with respect to a film surface, and an insulatinglayer that is provided on a surface of the heavy metal layer which isopposite to the magnetic recording unit, the method comprising: amagnetization reversal process of applying a voltage to the heavy metallayer through the insulating layer, and causing a write current to flowbetween one end and the other end of the heavy metal layer to reverse amagnetization direction of the recording layer.
 15. The write method fora magnetoresistance effect element according to claim 14, wherein in themagnetization reversal process, after applying the voltage to the heavymetal layer through the insulating layer, the write current is caused toflow between the one end and the other end of the heavy metal layer.